My employer has a FormLabs 3 resin 3D printer, and a little while back it started printing glitches into pretty much everything. It wasn’t anything major. It looked like the printer had just missed printing a nice, even line through the entire part. Or, to put it another way, like someone had taken a knife and cut a single slice out of the part all the way through. Not every part was affected, however, and we realized that it only happened in a certain area of our PreForm build space. I decided to dig a little deeper to see what could be causing this, because we were wasting a lot of resin. Turns out the glass optical window was very broken!
Not entirely sure what happened to cause this. Only thing we can think of is something got caught between the glass and the reservoir tank above it. Luckily, FormLabs was very easy to deal with in getting a replacement, and the replacement was relatively inexpensive compared to the price of a new printer.
But always check your optics!