You are operating with a lipo battery, that as you know, has a very high output, causing whatever you attach it to become more responsive and hit harder!
The amount of force the ARL (anti-reverse lever) is under is already strenuous because that little lever is the only piece that prevents your gears from rotating the opposite direction that they are made to operate!
The tension on the main spring that powers the piston pushes it's full force on the gears, which passes on from them to the ARL!
Abusive treatment, overuse, or perhaps just a faulty ARL, are more likely the causes of your little problem! Also; upgraded high tension main springs on non-upgraded geearbox internals (such as the ARL) is just asking for a world of hurt! To your weapon AND to your money. Or your mommy and daddy's money. Or where ever that money comes from it comes from somewhere and either way it's going to be spent.
Suggestion...buy a higher quality anti-reversal lever...or just go easy on the full-auto.
-Sergeant B.A. Dangle