ADDITIONAL SYSTEM INFORMATION :
Tested on Windows 10, OpenJDK 15.0.1 and OpenJFX 15.0.1

A DESCRIPTION OF THE PROBLEM :
I have javaFx application which is live science jdk 1.7 now I am working migration on OpenJDK 15. When I am calling setStartTime() on MediaPlayer the media-file stops smooth play Even it shows blank frame till I click on slider. It's coming with OpenJFX 14 as well.

REGRESSION : Last worked in version 8

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
just make a call player.setStartTime(Duration.minutes(2)); .
Time as per you convenience.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Media should play smoothly and there would be no any blank frame.
ACTUAL -
Media stops updating frames and at start shows blank frame till I click slider.

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Can provide Test application which is ready.
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CUSTOMER SUBMITTED WORKAROUND :
No Workaround found.

FREQUENCY : always