GX450 GPS data lockup

Hello all,
I’ve been experiencing GPS data coordinate lockup on several GX450 modems with AAF 4.8.0 through 4.9.3. The GPS timestamp is updating, but the coordinates remain fixed, even when I know for certain that the location is changing.

Powering down/up or hitting the reset button on the modem corrects the issue. Unfortunately, the problem seems intermittent, so I haven’t been able to replicate the problem in a controlled manner.

I’m streaming the data using NMEA format and a 2sec delay over the DB9 serial.

Any ideas?

Thanks in advance.