There's not much we can do to fix this, we use the FSX default jetway system, just with a custom model, but the animation is entirely out of our control. It's a known fact that the wheel lock into the ground is bugged in FSX, even default jetways do it sometimes, try for example the default CRJ-200 over a default airport, it has the same problem.
Sorry but, until we'll replace the FSX jetways system entirely, which is something we would like to do in the future, we must live with the FSX default system quirks.