the problem this time was that adding new measures to the start of the score then cut+pasting tuning for a bass tab will reset it to standard tuning on the measure where the tuning used to be. I think that's the best way to describe it. restarting the program fixed it, maybe just closing and opening the score would fix it too idk. I'd do some testing and see if it's fixed on the latest version, file a bug report if it's not, but idrc I just wanna write my song. if thou useth musescore feel free to do it in my stead :P