The answer to "what should I do if I suspect multis?" is always, "Contact the Titans."
The Titans will either be able to tell that they (almost) certainly aren't (in which case you just have to live with whatever they're doing), they'll be able to tell that they (almost) certainly are (in which case they'll be locked), or they won't have enough information, in which case they'll generally let you know and continue to monitor the situation, waiting for enough of a pattern to develop to be able to lock them. Or, as sometimes happens, not.