While not an issue with our camper TT, our gooseneck cattle stock trailer was wearing the front set of tires in the exact same way. Yep, bent axle. We had it replaced the axle for about $200, and bought 2 new tires.
While not known exactly why, I believe it was from possibly cutting too sharp at a gas pump island or parking lot.
Mark, Vicki, & Scout THE dog
2015 Hemisphere 282RK
2010 F250 Super Duty
1992 Goldwing Aspencade