Franco was benched before any allegations because he wasn't handling his frustrations well and needed to be a better teammate.
“Over the course of this season, there’s been probably multiple times that the way he has handled his frustrations have not been the way that we ask our players to uphold being the best teammate,” Cash said, per Marc Topkin of the Tampa Bay Times.
Wander Franco: Tampa Bay Rays Phenom Benched for Behavior, Attitude Issue - Sports Illustrated