From my testing, a power outage of more than a few seconds will ALWAYS trigger the powerflash. Less than that i when I get mixed results.
I would think (not that I am an electrical engineer, though) that you could build a circuit with a timer in in that would start when the power went back on, and only trigger the Powerflash after a certain number of minutes.
As for testing if the CM15A keeps running macros after power goes out, I guess you could write a macro that cycles a light on anand off every minute, for, say, 25 minutes.
Start it running (make sure it is working), then unplug the CM15a from the wall. Wait a minute or two, and then plug it back in. If it starts flashing the light again, it keeps running the macro. If not, then it stops running the macro when power goes out.
For me, I don't consider it a problem.
The If/then/else macros are written such that generally, only one would meet the proper conditions. Even if power went out in the middle of it running, and then came back, the whole macro only runs for a few seconds, at most.