Only reason I asked that is it's the simple things that often trip us up, if the bushings were dry at any contact points they would act like they were in a bind in certain positions, like when unloaded, then loaded during a gear change. The same thing may be happening if the bolts weren't torqued when the suspension was loaded. Something you may try is contacting the airbag manufacturer and see if they have any ideas.. I'm not really familiar with air suspension setups, and there may be something in the pressure?? Not enough?? Too much?? Idk... Often we seem to try and overcomplicate things when we try to troubleshoot things like this and overlook all the simple, small things that it could be.. Start simple and go from there..