I tried several times to enter / exit the menu of guilds. bonus from the guards of the guild that is, then no. sometimes the number of days the bonus is valid changes
This looks very similar to a current Known Issue we are aware of, Visual Issue: Guild Statue skill bonuses remain grey when active sometimes, instead of red, once all 12 Guild Tasks of the statue colour have been completed
But I have passed this onto the team to confirm if it is the same issue and investigate further, or if this is a different issue.