Whoa that's weird, I haven't seen this bug before .. do you mean the boss itself stops shooting? Or did you have enemies that were still alive during the boss? 😳 Share a screenshot if you can !
Oh that 100% explains it, are you using native pico 8, or a pico 8 EMULATION - pico 8 emulation sucks really bad unfortunately.... Like fake08 and whatever else is on Retroarch...