When a file upload is required, attempting to upload a file that exceeds the size limit gives only the message "Value is required." instead of the expected "File cannot be larger than nMB." unless another file has already been uploaded.
So when attempting to upload an 8MB file, I get this:
After uploading a smaller file, attempting to upload the same 8MB file throws this:
Laserfiche Forms Professional Version 10.3.1.635