[3.x]: Only one selected category remaining on article save

What happened?

Description

On selecting multiple categories for an entry and pressing 'save', only one is subsequently remaining.

Then if going back to select more, the multiple selections appear again, although not on save - and the entries do not appear in queries regarding that 'invisible' category. Have taken a series of screengrabs as attached.

Steps to reproduce

1. Select multiple categories.
2. Save entry.

Expected behavior

Entry should be in multiple categories.

Actual behavior

Entry is only in one category.

Craft CMS version

3.8.10

PHP version

3.8.11

Operating system and version

Linux 5.4.0-147-generic

Database type and version

MySQL 8.0.32

Image driver and version

Imagick 3.4.4 (ImageMagick 6.9.10-23)

Installed plugins and versions

Amazon S3 1.3.2
Asset Usage 2.3.1
AsyncQueue 2.3.0
Blitz 3.12.9
Bulk Edit 2.0.6
Cloudflare 1.1.0
Control Panel Nav 3.1.0
Docs 2.1.2
Feed Me 4.6.3.1
ImageOptimize 1.6.50
Json Client 1.0.3
Logs 3.0.5
Minify 1.2.11
Redactor 2.10.12
Redactor Custom Styles 3.0.4
Redirect Manager 1.1.1
Relabel 2.0.2
Retcon 2.6.1
Retour 3.2.10
Schedule 0.3.2
shopify 2.2.0
Tags 1.0.9
Typogrify 1.1.20
Views Work 1.3.0.7

Reproduce the issue in Craft CMS 3.8.10 using the listed category-selection and entry-save steps, then trace the category assignment and entry query paths. Done means an entry retains every selected category after saving and appears in queries for each category; verify against the reported MySQL environment and plugin context.