Was any definitive root cause determined in this thread?
I ask because I have been having the same issue and noticed it about the same time frame. My configuration is:
iPad 2 on version 8.1.x
iRig MIDI (30 pin)
Most of the time a reboot would fix, but not always. Very odd.
I spoke to iRig and they asked that I download the MIDI Wrench App to determine independently the iRig was seen by IOS, but also to see if I could send MIDI data outside of this Set List Maker app. I was able to do that when Set List Maker would not.
I just download IOS 8.3 and upgraded Set List Maker to the latest version. Now we wait to see if the problem continues.