Double content on the course page when you show custom content(sales page) without any content

### Reproduction Steps

Open a course and create custom content for the sales page but don't fill anything in it

### Expected Behavior

The page shown to visitors should be blank

### Actual Behavior

It shows the course page and has double contents

### Error Messages / Logs

+ Include any relevant error messages or log files
```
N/A

```

### System and Environment Information

System Report

```
Wordpress
-------------------------------------------

Home Url: https://elearn.gtec.tw
Site Url: https://elearn.gtec.tw
Login Url: https://elearn.gtec.tw/wp-login.php
Version: 5.4.2
Debug Mode: No
Debug Log: No
Debug Display: Yes
Locale: zh_TW
Multisite: No
Page For Posts: Not Set
Page On Front: 最新動態 (#4) [https://elearn.gtec.tw/]
Permalink Structure: /%postname%/
Show On Front: page
Wp Cron: Yes

Settings
-------------------------------------------

Version: 4.3.0
Db Version: 4.3.0
Course Catalog: 課程目錄 (#420) [https://elearn.gtec.tw/course/]
Membership Catalog: 會員資格目錄 (#421) [https://elearn.gtec.tw/memberships/]
Student Dashboard: 控制台 (#423) [https://elearn.gtec.tw/dashboard/]
Checkout Page: 結帳頁面 (#477) [https://elearn.gtec.tw/checkout/]
Course Catalog Per Page: 12
Course Catalog Sorting: date,DESC
Membership Catalog Per Page: 12
Membership Catalog Sorting: menu_order,ASC
Site Membership: Not Set
Courses Endpoint: my-courses
Edit Endpoint: edit-account
Lost Password Endpoint: lost-password
Vouchers Endpoint: redeem-voucher
Autogenerate Username: yes
Password Strength Meter: yes
Minimum Password Strength: strong
Terms Required: no
Terms Page: Not Set
Checkout Names: required
Checkout Address: hidden
Checkout Phone: optional
Checkout Email Confirmation: yes
Open Registration: no
Registration Names: required
Registration Address: hidden
Registration Phone: optional
Registration Voucher: optional
Registration Email Confirmation: yes
Account Names: required
Account Address: required
Account Phone: optional
Account Email Confirmation: yes
Confirmation Endpoint: confirm-payment
Force Ssl Checkout: no
Country: TW
Currency: TWD
Currency Position: left
Thousand Separator: ,
Decimal Separator: .
Decimals: 2
Trim Zero Decimals: no
Recurring Payments: yes
Email From Address: elearn@gtec.tw
Email From Name: 學習平台
Email Footer Text:
Email Header Image:
Cert Bg Width: 800
Cert Bg Height: 616
Cert Legacy Compat: no

Gateways
-------------------------------------------

手動付款: Disabled
手動付款 Logging: no
手動付款 Order: 1

Server
-------------------------------------------

Mysql Version: 5.6.48
Php Curl: Yes
Php Default Timezone: UTC
Php Fsockopen: Yes
Php Max Input Vars: 1000
Php Max Upload Size: 30 MB
Php Memory Limit: 2048M
Php Post Max Size: 30M
Php Soap: Yes
Php Suhosin: No
Php Time Limt: 90
Php Version: 7.4.8
Software: LiteSpeed
Wp Memory Limit: 350M

Browser
-------------------------------------------

HTTP USER AGENT: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.105 Safari/537.36

Theme
-------------------------------------------

Name: BuddyBoss Theme
Version: 1.5.4
Themeuri: https://www.buddyboss.com/
Authoruri: https://www.buddyboss.com/
Template:
Child Theme: No
Llms Support: No

Plugins
-------------------------------------------

BuddyBoss Platform: 1.4.7
Elementor: 2.9.14
Elementor Pro: 2.10.3
Element Pack: 5.3.1
GamiPress: 1.8.8
GamiPress - BuddyBoss integration: 1.0.3
GamiPress - LifterLMS Group Leaderboard: 1.0.0
GamiPress - LifterLMS integration: 1.0.7
GP Conditional Logic Dates: 1.0.15
GP Date Time Calculator: 1.0-beta-4.0
GP Limit Dates: 1.0.22
Gravity Forms: 2.4.19
Gravity Forms Signature Add-On: 3.9
Gravity Forms Signature Add-on by ApproveMe: 1.5.5.8
Gravity Forms Survey Add-On: 3.5.1
Gravity Forms User Registration Add-On: 4.5.3
Gravity Perks: 2.1.9
LifterLMS: 4.3.0
LifterLMS Assignments: 1.1.9
LifterLMS Gravity Forms: 2.0.1
LifterLMS WooCommerce: 2.0.15
Loco Translate: 2.4.0
reCaptcha by BestWebSoft: 1.57
RY WooCommerce Tools: 1.6.6
User Role Editor: 4.55.1
WooCommerce: 4.3.1
WP E-Signature: 1.5.5.8
WP E-Signature Business add-ons: 1.5.5.9
WP Super Cache: 1.7.1

Integrations
-------------------------------------------

BbPress: No
BuddyPress: Yes
LifterLMS Gravity Forms: Yes
WooCommerce: Yes

Template Overrides
-------------------------------------------

content-certificate.php (ver: 3.18.0): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.18.0)
achievements/loop.php (ver: 3.14.0): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.14.0)
achievements/template.php (ver: 3.14.6): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.14.6)
certificates/loop.php (ver: 3.14.0): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.14.0)
certificates/preview.php (ver: 3.14.0): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.14.0)
course/author.php (ver: 3.25.0): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.25.0)
course/lesson-preview.php (ver: 3.19.2): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.19.2)
course/syllabus.php (ver: 3.24.0): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.24.0)
loop/author.php (ver: 3.0.0): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.0.0)
loop/content.php (ver: 3.14.0): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.14.0)
loop/featured-image.php (ver: 3.35.0): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.35.0)
myaccount/dashboard-section.php (ver: 3.30.1): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.30.1)
myaccount/header.php (ver: 3.14.0): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.14.0)
myaccount/my-grades-single-table.php (ver: 3.24.0): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.24.0)
myaccount/my-notifications.php (ver: 3.30.3): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.30.3)
myaccount/my-orders.php (ver: 3.17.6): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.17.6)
myaccount/view-order.php (ver: 3.35.0): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.35.0)
product/access-plan-pricing.php (ver: 3.29.0): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.29.0)
quiz/results-attempt-questions-list.php (ver: 3.17.8): /home/httpd/vhosts/gtec.tw/elearn.gtec.tw/wp-content/themes/buddyboss-theme/lifterlms/ (ver: 3.17.8)

```

This issue has be recreated:
+ [ ] Locally
+ [ ] On a staging site
+ [ ] On a production website
+ [ ] With only LifterLMS and a default theme

### Browser, Device, and Operating System Information
n/a

### Related User Information
There’s an alternative solution
### Alternative Solution
Fill the custom content with something, or choose a different sales page option.

HS-130205