I have heard before that this happens from time to time. I don't think it's a new occurrence.

73, John Brier KG4AKV

On Tue, Jul 7, 2020 at 3:19 PM Ronald Parsons via AMSAT-BB amsat-bb@amsat.org wrote:

On the SO-50 1900Z pass I noticed the carrier was shifting down about 4 kHz randomly. Has this been noticed lately? Ron W5RKN _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb