The writing was on the wall. "behind the 8 ball" and "coming along at a slower place than I would probably like" are not what you want to hear.
http://www.csnwashington.com/redskinsblog/gruden-seastrunk-bit-behind-eight-ball
Haven't found anything to support the "character issues" other than a few tweets where people are 
guessing that is the reason. Washington still has 2 spots open on their PS. Could still add him but they've said they have no plans.
		
 
I agree the writing was on the wall in Washington, but you could've argued the same thing about Crowell in Cleveland prior to that fourth preseason game.
Lache produced with the ball in his hands, but to not even be invited to the practice squad despite spots open and to not be claimed by another team speaks volumes.
I like the kid's ability to run the football and make plays, but there are clearly other issues at play here. This league rosters dudes you wouldn't exactly want your daughter hanging out with. The NFL puts murderers, thiefs, liars, swindlers, etc on the field when they can play. To get passed on by all those teams after making explosive plays all preseason is a major red flag IMO.