My F1 + F2 keys were bound to party member selection (as per the default) and then unbound (as it really bugged me when trying to pip), the other F keys were unbound on my characters.

I will double check the region names when I get home, but I'm pretty sure I set up wow1 > region1 (both in PiP and command editor) > F1 and wow2 > region2 > F2. I removed all the regions on my maximiser and made new regions, is it possible that some get saved elsewhere? (i.e. not where you can see them on the set up page).