I believe this factors in when you see a players' determination nosedive. I've also seen random off-field events influence this too. Usually it will notify you with an email if there is something specific.
Do you currently have the player being mentored by other teammates?
With fears of COVID-19 running high around the world, many nations have ordered different levels of social isolation, including some requiring mandatory quarantines. As a result, FM has been offered free all week, with an extension to this Wednesday. This is the perfect time for new players to...