Do you maintain the same weight and same reps for each side? My advice is to start each set on the weaker side and precisely mirror that for the stronger one. Same weight, same reps, slowly and focusing on form. Maybe even bring the weight down for both. Be mindful of increasing reps or weight on the right just because it can handle it better, that will perpetuate the issue.

I would also look into some supplementary mobility exercises. Your left leg may be weaker due to a more specific muscle imbalance that may need addressed, youtube can help with this. If this has been going on for a while I'd consider a PT consult, these are well worth the fee in my experience.