I am having the same problem. Switching smart on and off did not fix the problem.
After troubleshooting it appears that, although slots A and B still say they are linking to their respective stored programs, they aren’t really. For example, for slot A, i was able to tap the slot, tap replace, then tap the same saved program and it worked!
… BUT, slot For a slot B, the respective program was completely corrupt. I had to tap Edit and re-enter all the program settings.
Also of note, before fixing this, I went to the physical unit and found that the budget for A and B were set to 0% — I assure you they were all 100% and working before the problem happened. I also had to set them back to 100%, though that itself was not the fix. Overall it seems that the program slots and saved programs were simply corrupt.
If you care to inspect my unit, my Mac is: 44675501b320 (firmware 0031)