Latency changes midway through performance

Hi there, apologies if this has been looked at before, but I couldn’t find anything similar when searching.

When playing guitar through an interface into Ableton Live, the latency seems to change and increase out of nowhere. One minute it’s fine and playable, and the next there will be a small digital *crackle* and the latency noticeably increases, making it unplayable.

Does anyone know what could be causing this? Loose connection, buffer size settings, user being an idiot, etc? Any ideas gratefully appreciated!

Presonus Studio 26 interface
Macbook Pro 2019
Buffer size: 256