I have never had one break in 10 years of using a levelup system. However, I have seen that and can speculate on possible causal factors.
Over torqued bolts.
Side load. Raised too high in windy conditions.
Rear Wheels off the ground.
Too much “rocking the boat”.
Corrosion as previously mentioned.
Meanwhile, I would suggest replacing the OEM hardware with Grade 8’s. (They are supposed to be grade 8 anyway)
Ď18 Sunseeker 2800QS