Anycubic Photon M3 Max Strange printing issue.

First of all I have no pics because the printed parts are in the trash. Ill try to describe this as best that I can. I have been printing large character models on my machine. Actually with pretty good success. Now where I have been running into issues with is with the bases that the model would be standing on. The prints print but they are all miss proportioned. For example... A round base will end up being more oval than a circle in shape. This happens on the horizonal on the model not vertical. Using Chitubox as a slicer for reference. Have wasted a good amount of resin so far messing with it. It prints fine but the shape is all wrong. I have not noticed this on other parts of figurines, Just bases. Currently running a print of a character head to compare it with a print of the same head done on my Satern. Some thoughts im having are that I am under exposing the print. Thus causing a thinner layer. Last print was at 3 sec. Though I have had basically the same issue with an exposure time of 3.5 and even 3.7. Current test is running at 4 sec. Any thoughts?