Having them throwing red flags all around might be a red herring, but since this manga is pretty much cliché they might actually be as scummy as ppl noticed.
Most of the girls in this manga are quite dumb or bitchy, so having that new girl be some kind of manipulative bitch that wants her reverse harem wouldn't suprise me at all.
Imo I think her and boss are in some kind of relationship. If she is manipulative bitch then I presume she allows her boss to do perverted stuff to girls, while she is having fun with the guys, but I might be totally off and the culprit might be some third-party.
All in all unless I read LN I won't know and I will need to wait like everybody else xD