A while back, I received a question from a modeler who was attempting to 3D print some thin parts and they were having issues with the parts warping rather than maintaining their desired shape. All 3D printing resins experience some level of "shrinking" when they cure. The amount will depend on the specific resin. Geometry of the part can also impact the impact of shrinkage as well, but there is something else to consider first that is much simpler to resolve.
Recently, I removed a batch of prints from my printer, placed the in my alcohol cleaning bath and promptly forgot about them until several hours later. By this point, the thin sections of the parts had warped rather significantly. As they sat in the cleaning bath, they absorbed the alcohol and swelled. Under these conditions, the resin grows and becomes a little softer, resulting in the wavy shapes you can see below.
Some might see this and think the parts are ruined, but just wait! ...literally, just let the parts sit and wait for the alcohol to evaporate out. As the alcohol evaporates, the parts will shrink back to the original shape they had coming off the printer. In this case I awaited a few days and the parts returned to normal. If I were to "post cure" the parts under the UV lamp before I let the alcohol evaporate, i would have locked in the wavy shape and had to throw the parts out. So, it is important to let this evaporation process occur before you go to the UV lamps.
Ideally, you won't leave your parts in the cleaning stage as long as I did. A good 10minutes is usually more than sufficient to get the uncured resin dissolved away. However, if you find a situation where you have thin sections on your 3D printed parts that are coming out of the cleaning stage looking a little soggy, just give them some time to dry out and see if the issue remains. Hopefully it was just a little excess alcohol absorption that was your issue.