Changed 12V Battery... Now FM Radio Frequently Loses Reception

Recently, we had to change the 12V auxiliary battery on our 2010 Prius IV.

Everything went smoothly and the entire procedure took less than 20 minutes.

We thought everything was good, until we turned on the radio.

Since we changed the 12V battery, the FM radio (which is part of the NAV console) has great difficulty keeping any station tuned. Before changing the 12V battery, we could drive around and listen to our favorite FM radio stations; now, the radio frequently loses reception, and our music frequently gets interrupted with static.

It's been a couple months, and the situation has not improved. We took a look at the antenna, and nothing looks out of the ordinary.

It seem odd that changing a 12V aux battery would cause this problem, but we have not made any other changes (not even an oil change) for several months.

Is it possible that changing the 12V battery fried something just enough to cause FM reception issues? If so, what is the solution? If not, what is causing the problem?

Note that we are still under an extended warranty.

 

The FM radio is still experiencing this issue. We don't normally listed to AM radio, but noticed that it seems to have a similar issue.