Every time I open a project that uses Petaluma font, it says I’ve got missing fonts and provides a grid for me to select alternatives.
However… if I just click “OK” and proceed to the project, I don’t notice any problems (yet). 
Nevertheless, it’s annoying to receive this warning every time I open up a Petaluma font-based document.
Thanks!
Preferences—General—Files. You can uncheck this option.