LGB 41700 G Scale RHAETIAN RHB TANK CAR

I was very happy with this tank car, but when I put it on my track it frequently derailed! I eventually discovered the trucks were flexing due to what appeared to be bad parts! LGB replied to my complaint and said that is the way the truck is designed to prevent derailments! But I am finding just the opposite! None of my other LGB cars have such a flexible truck - they are all rigid. This is VERY poor for an LGB product! For an over $100 LGB tank car, one expects and deserves much higher quality! This is the very first and only issue I have had with an LGB product in my over 20 years using LGB trains!