just so I am understanding what you are saying, have you uninstalled Sunflower, or did you update it and it now works ok with iReal Pro?
Thank you for your offer for future testing. We have a number of test Macs, probably sufficient for our needs currently, although we can keep you in mind. My comment was related to all the various audio interfaces available—and any drivers. As you have found out, problems can occur with either our software or others (or the OS itself).
Hopefully your other Macs will work successfully now also.