Follow-up: When I mentioned the delay in the radio tuning, the service advisor immediately knew that it was related to the RDS. With my radio, I was unable to turn off the RDS. The previous dealer who had replaced my radio unit did not set it properly to the US (United States) region. Now I again have access to the PTY and RDS functions, and the ST symbol appears on the display.

The service advisor told me that they do not have a fix for this issue, except to turn off RDS.