Hallo Frank, list!
preempttion patches, however I may add, that "normal" Pd patches that don't use the network-connection are running very stable and without xruns.
I only want to add, that I experienced a similar problem one month ago: I also made a gui-patch and a audio-patch and wanted to play them with 2 instances of pd, but it was not useable at all ... then I integrated them in one instance and it was no problem ... but I didn't figure out the problem unfortunately ...
LG Georg