From what I can tell the basic interrupt structure looks to be ok.
Unfortunately, the way the various files are written, all of the ReEnterPBP routines don't appear in the .lst files, so it makes tracking what they're doing next to impossible.

When you have ReEnterPBP-18 and ReEnterPBP-18LP together they use a boatload of ram, over 136 bytes for the PBP context.
That puts many of the variables outside the access bank, so it's possible there's a bank select issue in there somewhere.