To reproduce this:

1. Run any Swing program (e.g., SwingSet2 or J2DBench) with the metal pipeline:
$ java -Dsun.java2d.metal=true -jar SwingSet2.jar

2. Drag the window to the other screen

3. It will immediately crash with the following assertion error:

$ java -Dsun.java2d.metal=true -jar SwingSet2.jar
metalEnabled=1
     Metal: Supported, feature set macOS GPUFamily2 v1

Metal support is present
-[_MTLCommandEncoder dealloc]:70: failed assertion `Command encoder released without endEncoding'
Abort trap: 6

I also reproduced it with a small test program with a single JButton.

This is a regression caused by the fix for JDK-8251484. If I locally revert that fix, it works.