JOSM freezes from time to time without clear indication why

[dieterdreist]

I get freezes in Josm several times a day, console output is this:

local revision is 18559, latest available revision is 18559 - using local revision 18559
starting josm...
josm started with PID 2504
2022-09-20 09:43:48.759 INFO: Log level is at INFO (INFO, 800)
Warning: the font "Times" is not available, so "Lucida Bright" has been substituted, but may have unexpected appearance or behavor. Re-enable the "Times" font to remove this warning.
Warning: the font "Times" is not available, so "Lucida Bright" has been substituted, but may have unexpected appearance or behavor. Re-enable the "Times" font to remove this warning.
2022-09-20 09:43:50.630 INFO: Detected no usable IPv6 network, preferring IPv4 over IPv6 after next restart.
2022-09-20 09:43:50.667 INFO: Restart [/Library/Java/JavaVirtualMachines/adoptopenjdk-8.jdk/Contents/Home/jre/bin/java, -Xmx2048M, -Djosm.home=/Users/martin/.josm-cai, -Dsun.java2d.opengl=true, -jar, /Users/martin/bin/josm-archive/josm-18559.jar]
josm terminated

it says "josm terminated", and "restart" but what I see in the GUI is Josm with a "waiting spinner" and neither restarting, nor being reactive to any command (I have to kill it and restart manually).

Maybe it has to do with IPv6, because during startup, there is this message:

INFO: Detected usable IPv6 network, preferring IPv6 over IPv4.

before the crash, I get

INFO: Detected no usable IPv6 network, preferring IPv4 over IPv6 after next restart