Is a 315 squat "trained"? That's weeks into the LP for some novices.
OP -- I started running a mile once a week about 2 months ago. It took like 6 weeks until my acchilles tendons adapted to the point I wouldn't be limping the next day, and I squat a lot more than you. Anyway this is a pointless discussion, doing thousands of reps vs 5s produces different stresses and thus requires different adaptations. Whether you're more susceptible to the effects of those stresses is a function of many variable, and is most likely despite your training and not because of it. Ultimately it doesn't matter.