The staples holding down flashing on roof edge coming up.

The staples probably worked loose through vibration and bouncing down the road.
The real question is, why? Maybe the staples are not quite long enough or not hitting something solid?

I'm guessing there is no easy or simple fix. What you are doing is probably the best solution. Take your time snd replace the staples with screws.
What is forever tape? Is it similar to Eternabond?