Shimano Sora rear derailleur BROKE OUT instead of dropout

This is to alert you that shimano sora rear derailleur is a fragile product, so, you should be allways sure you bike is well adjuatwd and that you have a good safaty distance from the low gear to the wheel.
Probably the dropout would work well with other shimano deraileurs, like 105 but with this ou it is actually stronger than it should be!
PS: shimano compatibility chart did not have any other deraileur for 9 speed sora shifters.

[@thewanderer673]

Same happened with me. Did you find the cause?