The link below has an image of my waterfall during part of the SO-50 pass. The two yellow arrows show two instances of several more that occurred during the pass. The time scale in minutes is on the right of the waterfall.

https://drive.google.com/file/d/1Rl0LMMIHc_By96anqySUXmLAzURtQnH-/view?usp=s haring

The down-shift was about 4 kHz although it was somewhat hard to measure accurately due to the Doppler shift causing the signal trace to bend down and to the right on the picture.

Ron W5RKN