Tag scores update is supposed to happen at 03:00 UTC every day. Tag scores are updated by a scheduled job that is time consuming and often times out (see for example the answers for Tag info not updated regularly on profile? and Tag scores have not updated; script did not run).
In the past month or two, the issue with not updating the scores has gotten much worse. Tag scores are now regularly not updated for 2-3 days in a row. The job fails more often than it runs which obviously lowers usability and appeal of tag badges (which are not awarded when the script fails) and scores to some extent.
I can also guess that if a job fails on consecutive days, it only makes it harder to make it work as it has more and more tags and answers to recount.
This issue happened in the past but not to the extent it's happening now.
Please do not close it as duplicate. I'm creating a separate post as I've been asked to do it by Adam Lear in a comment for the answer for the first of the linked questions. Other posts reporting this issue have accepted answers which makes them difficult to track for the SE team.
I've been writing down whether the scores were updated or not every day in April.
The results are:
Day 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Updated - - - ✓ - ✓ - - - - - ✓ - - - Day 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Updated ✓ - ✓ - ✓ - - ✓ ✓ - ✓ - ✓ - -
The update succeeded on 10 days, failed on 20. The situation got somewhat better in the second half of the month. Has something been done about it?