Firefox: some website links trigger the popup blocker

Describe the bug
When using vimium, there are 'some' websites which trigger the popup blocker. I'm providing all the information I have here, but don't have the knowledge to differentiate what's special about this site in particular.

For clarity, the website in question is a Malaysian website which allows you to earn some cash out of the referral rewards given when purchasing at online retail sites. Accounts are free but require some personally-identifying information. I can provide a dummy account if that would help (so as not to unfairly require anything of anyone else).

To Reproduce
Steps to reproduce the behavior:

1. Go to URL https://www.shopback.my/survey-wall
2. Click on 'Shop Now'
3. An internal 'pop-up' (within the page) shows up with some marketing material and a link saying "go to survey wall now"
4. Select the link (either with f or F, no difference)
5. Opening the new page is blocked by Firefox
6. Clicking the link with the mouse (left or middle click) both open the page in a new tab without the popup warning.

Browser and Vimium version

This behaviour is not new. These are my current versions, running on Arch Linux.

Firefox 93.0
Vimium 1.67

Additional

I have seen https://github.com/philc/vimium/issues/3539 but using Ctrl while selecting the link doesn't help.

Start by reproducing the issue at https://www.shopback.my/survey-wall in Firefox 93 with Vimium 1.67, comparing keyboard selection with left- and middle-click behavior. Done means identifying why the keyboard-opened link is blocked and making it behave like the mouse activation without regressing other links.