Having read the "Recall Notice", it seems the problem with the flare cartridges is failure to fire.
So it would appear that they're not dangerous to use, just likely to fail when you need them.
Thus it would seem that you could keep them, but hold them in reserve to only back up the new ones that are more reliable.
The final problem would be what to do with one that mis-fires, but that' the same as with a mis-firing shotgun shell:
If it doesn't fire, give it 15-30 seconds, then eject it, let it lay for awhile, and if it is still dead after a minute or so, it's no more dangerous than an unfired shell.
Is this correct?
Subsequent safe disposal is another matter, of course.
Joe. :teeth :thup