SOLVED: Trickplay enabled, but not working

[mjeshurun]

What CPU/GPU do you have in your system?  Try turning off all hardware acceleration for trick play?

Intel Core i7-10700 CPU @ 2.90GHz
CometLake-S GT2 [UHD Graphics 630]

As you suggested I disabled hardware accelerated MJPEG encoding in the Trickplay settings and restarted the task, but the error is still happening in the log.