If the active melody voice is not Lead 1 and a polyphonic Theorytab created in HookPad 1 is opened, whatever is on Lead 1 of the loaded tab is copied into the active melody voice, erasing the original contents on that voice.
Hi @HertzDevil, I fixed this today in 2.10.8. Once again, thank you for the amazing bug reports! Hookpad would be so much more buggy w/o you!