Problem of cutting high on right side

I am having a problem of the mower Model # LM2102SP cutting about a quarter inch higher on the right side. I am using the the high lift blade. I typically over lap by a few inches and still is evident. Only if I overlap by more than half will it not show up. I have not hit any heavy debris and there no extra vibration to indicate any anything bent. I do cut using the self propelled feature set at very slow. Its like the height adjustment is not exactly even on both sides. It does happen regardless of set height. Didn't know if there is anything I need check or I can fix/correct myself. I bought the mower back in Spring '18. It seems like it has always done it but lately now it seems more evident than before.