Hi Filipe! Thank you!
I'll look into the windows issue.
I don't use PYIN to extract the fundamental frequency, only the barebones autocorrelation approach. I had planned to switch to YIN or SNAC, but I never got around to it.
I've never had anyone contribute to a project of mine, I'm new to this 
.
I'd gladly accept contributions! We can continue discussing this on discord.