For my long years of participating in a bounty campaign, I have seen several bounty managers that update their spreadsheet during the last week of the campaign. Most of them pay so I won't consider it as a red flag for scamming since I also experience an updated sheet and a very active manager but in the end, the campaign does not pay a single cent to its participant.
Actually, it will depend on who the bounty manager is.
there are Bounty managers that always update the spreadsheet regularly every week.
There are some bounty managers that update the spreadsheet after several weeks or in the last weeks.
And there are also some bounty managers that update the spreadsheet after the bounty ended.
Each has its strength and weaknesses. But, as long as the BM is still active, in the forum or even in the social media or telegram group, I think that it is still normal. but, if there is no updated news, not active for a long time, and no clear information even after some week's bounty ended, the BM may get red flag or scam accusation.
We can't expect anything great from bounty programs as we also don't know about their arrangements to the project itself.
Maybe, some are not diligently doing their job because they have other factors that they are considering, like the possibility of not being paid as well.
This is why in most of bounty programs, can be run by any person. Unlike with btc-paying campaigns, most have established reputation already.