When attempting to load a .p8 cart that exceeds the 65535 character limit (one that may have been created by an external editor or tool), PICO-8 silently drops lines at the end of the cart and does not report errors. It then accepts to save the (now corrupted) cart when pressing Ctrl-S, overwriting the original file.

Here is a sample cartridge for testing purposes; notice that the last print() line disappears when loading it.

One more observation: sometimes, when the 65535 character threshold lies in the middle of a Lua statement, a loading error does appear. I have been unable to identify when exactly.