Some blog post tags give 404 error

I have created a sorting system using tags and it was working great. But one day I came back to continue to work on content management so that user could input their own data for some page elements. Then I noticed that some site posts could not be opened leading to a 404 page. I did some testing and found out that posts with some specific tags would lead to 404 page, but when i change out to a different tag the page would work and load properly.
Here is a link to the video for the problem
Explanation of the video:
first I have a blog post created. Than I add t tag “Glosas” by using the tag the post is placed in the page “Glosārijs”, then I go to the page “Glosārijs” there the new post is found. i click on the post it leads to 404 page. After that I change the tag of the same post to “Metodes” that moves the post to the page “Metodes”, after I go to the page and try to apen the post and it opens correctly. Then a change the tad back to glosas and find it in the appropriate page it has been found and when opened shows 404 again, after i ad metodes tag to it and it is also found in the metodes page, but leads to 404 page because it thas the tag glosas on it. As i understand its something to do with the specific tag.

I have tried to remove tag and add it again but didn’t help. I checked all of the routes but they haven’t changed. This worked perfectly yesterday.