Due to how tabs are saved in the .p8 file format, they can cause overflows into the sprite sheet. Each tab is saved as 6 characters in the .p8 file. However, those are not counted as part of the character limit until the cart is run or saved. If you have a cart that has multiple tabs and is at or just below the character limit, trying to run or save the cart will cause part of the code to overflow into the sprite sheet before giving an error, either "**** save failed ****" when saving or "program exceeds char limit" when running. In testing I've also had Pico-8 completely crash when trying to run a cart whose tabs push it over the character limit, but I was unable to replicate this.

(pico-8 version 0.2.6b)

The best way to solve this in my eyes, is to have each added tab of code add 6 to the character count in the code editor. That way, in the same way it's impossible to type over the character limit, it'd also be impossible to have tabs push over the character limit and overflow into the sprite sheet.

Thank you!