Off the top of my head...
RID Prowl: ball joint socket cracked
Animated Deluxe Bumblebee: ball joint socket cracked
EZ Transcanning Hyper Hobby Bumblebee - clear arm socket cracked... both sides
United Sons of Cybertron Clear Rodimus: hairline fractures in one clear arm socket after ONE Transformation and Combination with FP Crystal Protector armour...
Anyone see a TREND here? At least Fansproject understands, the Crystal Protector set has a red clear plastic with a bit of a rubbery "give" to it.
Because of my bad experiences with Takara/Tomy clear products I am afraid to open and transform my eHobby United Clear Decepticon set now...
The two other notable breaks I had included snapping the tip of a rear window off my friend's Alternity Megatron (notoriously fragile line)
and last but not least... breaking the arm off SPIKE from my Fort Max showing some kid how Headmasters were interchangeable!!!