Well I don't see any problem with it because as fas as I know those bounty managers have the consent of their clients. Besides, a bounty manager has a lot of on going project that is why their signature and avatar will always vary depends on what they want to wear.
Yes, there is no problem with that, but each participant can also assess it very carefully, where a manager only uses a signature for a campaign that is paid for in the form of BTC, while managing other project campaigns, so that the impression can arise that the project is it's not good, because the manager doesn't even follow the project.