A workaround I've figured out is to go into the app's full-screen preset view and click the little folder icon in the lower right corner.  This pulls up a mini-browser for all the saved preset files.  Navigate "up" and look for the the midimaps folder.  Copy/paste the preset file into the same folder to make a duplicate of it.  That duplicated file then properly loads the saved midi map settings.  It only works as long as the app is left running.  If the app is closed and reopened, the midi-map file must be duplicated again to a new preset file. 

Definitely seems to be a bug with the app.   I submitted to Modartt customer support, will report back here if I hear anything.

When I click the button to “Browse” it takes me to the Files app, but does not put me in the Pianoteq folder.  In fact, I can’t find a Pianoteq folder anywhere on my iPad locally or in the iCloud Drive folders. 

I’m doing this with standard global mappings that aren’t associated with any patch preset. 

I’ve tried re-installing, tried it in both plugin mode and standalone mode, and I keep getting the same result. 

Any ideas?