When I had a BAL system, one of the cables was also "loose". If it was open either the top or bottom was loose, and closed the opposite was loose. I read either on their website or the manual that came with the trailer that slack was normal. I can't say if an inch of play is normal, but if it's working okay I would leave it alone. They can be adjusted though. If you are under warranty I would let the dealer do it.
On a side note, the screws or bolts holding the motor above those slides have a tendency to back out. It happened to me also. You can check by partially opening the slide and looking over the top of it. This should allow you to tighten any if necessary, but it is very tight in there on a couple bolts.
Steve & Sue
2017 Grand Design 297RSTS Travel Trailer
2017 Ford F-350 Lariat Crew Cab diesel 6.7 SW LB 11,500 lb GVWR package
Former: Crossroads ST26RB