A couple of things.
Firstly, Marvin Johnson is good mates with Marcus Browne after they were at Middlesbrough together so may have just been down watching his mate play.
Secondly, he has history for "forcing" a move away from clubs. We benefitted from him not playing at Motherwell to get a move to us, and lost out when he was sulky before getting a move to Middlesbrough (although the £2.5m fee soften that blow). I wouldn't be surprised if this is part of a plan to orchestrate a move away.
Finally, Johnson has had a bit of an attitude problem at several clubs and with several managers. It's no surprise that he's fallen out with his current one. But I think all would love to have him back. Tyler Burey had one occasion where he reacted to (racist?) abuse from his fans and was open to numerous options at the beginning of pre-season rather than jumping at the first offer. And several still say that he has an attitude problem and should never be anywhere near our club!