Voltage Meter Reading

Yes, Both are trying to tell you something is not right... regulator or generator Early Coupes had a 17 Amp gen. Sometime that was traded for a 35 amp gen Check for bad wire ends etc.

I noticed the other day when I was out and about that my Voltage Meter, which normally shows 13-14 volts, occasionally jumps to 16+ volts for a few seconds and then drops back to 13-14 (see picture) .  I have just installed a new Odyssey battery last week due to my old one giving up the ghost.  I recently had the AD checked for the voltage regulator...no issues.

What might the issue be?  Should I be concerned?  Amp Gauge wiggles + to - back and forth when voltage is up.