Currently when I come to a stop the voltage is bouncing.
If you mean it goes down, then back up, and then holds, I think this just what happens while braking.
Mine does that - with a less-than-a-year-old 130A Toyota alternator, a less-than-a-year-old Odyssey 31M-PC2150 battery, and every cable in the alternator/battery/fuse-box system upgraded and
with a few extra grounds added.
Alternators control the current they generate by running more or less current through them as they spin. They can either spin faster or
run more current through them, to produce more current. When you brake, the spin decreases, so less current is produced. To make that up, the alternator's got to run more current through it. Combined with incandescent brake lights, if you have 'em, braking is a sudden drop in current output coupled with a sudden jump in current demand - which will manifest as a voltage drop.
It's also possible that the voltmeter on the dash isn't entirely trustworthy. Can you replicate the voltage bounce while parked, just by applying and releasing the brakes? If so, run a multimeter into the cab and see if its voltage reading agrees with the dash gauge.