As reported by yush, here: https://lalescu.ro/liviu/fet/forum/index.php?topic=6844.0 , he discovered some ugly bugs if you rename or modify an activity tag (the constraints of type max activity tags per day/real day/week are not correctly updated), and I fixed them.
Unfortunately, I cannot release too soon, I am waiting for the active translators to finish their work. Hopefully on Monday morning, in about 5 days from now (on 2026-06-15) we'll have FET-7.8.7 to fix these bugs. Until then, on https://lalescu.ro/liviu/Backup-fet/ you can find the fixed version, in sources form.
I deeply apologize!