I have been discovered an issue with router associated with com_tags/com_content.
There are two menu items:

1. Category Blog. Alias: blog.
2. Tags > compact list of tagged items. Alias: tags.

I noticed some items with incorrect URL:
Quantum Manager 1.5.0 released (https://mydomain.com/blog)
Quantum Manager 1.3.1 released (https://mydomain.com/blog)

Other items have correct URLs which leads to the page, e.g.:
https://mydomain.com/blog/quantum-manager-1-4-0-released

I switched to Cassiopeia to check out and the issue is the same:

Menu item options:

So, in some cases the path to the article is wrong...

If this issue is known - ok. I just shared the info which recently was discovered.

System information (as much as possible)

Joomla 4.2.5
PHP 7.4 / 8.1