The test javax/swing/plaf/aqua/CustomComboBoxFocusTest.java fails with the following output :

#section:main
----------messages:(5/208)----------
command: main CustomComboBoxFocusTest
reason: User specified action: run main CustomComboBoxFocusTest
Mode: othervm
Additional options from @modules: --add-modules java.desktop
elapsed time (seconds): 5.925
----------configuration:(3/40)----------
Boot Layer
  add modules: java.desktop

----------System.out:(11/375)----------
Wait for screenshots...
Request focus on reference
Capture sceeenshot of reference
Target bounds: java.awt.Rectangle[x=0,y=46,width=80,height=26]
Target location: java.awt.Point[x=0,y=91]
Request focus on custom
Capture sceeenshot of custom
Target bounds: java.awt.Rectangle[x=0,y=92,width=80,height=26]
Target location: java.awt.Point[x=0,y=137]
Done
Compare screenshots...
----------System.err:(22/2882)----------
metalEnabled=1
2020-01-31 15:09:02.386 java[2168:87918] CoreText note: Client requested name ".SFNS-Regular", it will get Times-Roman rather than the intended font. All system UI font access should be through proper APIs such as CTFontCreateUIFontForLanguage() or +[NSFont systemFontOfSize:].
2020-01-31 15:09:02.386 java[2168:87918] CoreText note: Set a breakpoint on CTFontLogSystemFontNameRequest to debug.
2020-01-31 15:09:02.387 java[2168:87918] CoreText note: Client requested name ".SFNS-Bold", it will get Times-Roman rather than the intended font. All system UI font access should be through proper APIs such as CTFontCreateUIFontForLanguage() or +[NSFont systemFontOfSize:].
2020-01-31 15:09:02.388 java[2168:87918] CoreText note: Client requested name ".SFNSMono-Regular", it will get Times-Roman rather than the intended font. All system UI font access should be through proper APIs such as CTFontCreateUIFontForLanguage() or +[NSFont systemFontOfSize:].
2020-01-31 15:09:02.392 java[2168:87918] CoreText note: Client requested name ".SFNSMono-Regular", it will get Times-Roman rather than the intended font. All system UI font access should be through proper APIs such as CTFontCreateUIFontForLanguage() or +[NSFont systemFontOfSize:].
2020-01-31 15:09:02.392 java[2168:87918] CoreText note: Client requested name ".SFNSMono-Regular", it will get Times-Roman rather than the intended font. All system UI font access should be through proper APIs such as CTFontCreateUIFontForLanguage() or +[NSFont systemFontOfSize:].
2020-01-31 15:09:02.394 java[2168:87918] CoreText note: Client requested name ".SFNS-Regular", it will get Times-Roman rather than the intended font. All system UI font access should be through proper APIs such as CTFontCreateUIFontForLanguage() or +[NSFont systemFontOfSize:].
2020-01-31 15:09:02.395 java[2168:87918] CoreText note: Client requested name ".SFNS-Bold", it will get Times-Roman rather than the intended font. All system UI font access should be through proper APIs such as CTFontCreateUIFontForLanguage() or +[NSFont systemFontOfSize:].
java.lang.RuntimeException: Test failed.
at CustomComboBoxFocusTest.main(CustomComboBoxFocusTest.java:90)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
at java.base/java.lang.Thread.run(Thread.java:832)

JavaTest Message: Test threw exception: java.lang.RuntimeException: Test failed.
JavaTest Message: shutting down test

The failure was not observed on OpenJDK builds jdk-14-ea+33_osx-x64, jdk-15-ea+7_osx-x64

The reproducibility: 100%
Steps to reproduce:

$ jtreg -Dsun.java2d.metal=true -testjdk:[path_to_lanai_home] test/jdk/javax/swing/plaf/aqua/CustomComboBoxFocusTest.java