Ouups that was a bit of a botched bug report sorry.
This bug is bugging me since two years. But the current configuration is:
JUCE 8.0.8
Max 8.6.5
on macOS 15.5
Last known good JUCE version is 7.0.3 but there might be later ones that still work.
This version supports both host provided context menu in e.g. REAPER and no crash in Max
Just used the summer sale to upgrade to Max 9. I can confirm it is working there. The only thing that makes me think it is worthwhile to investigate a little bit is that with JUCE 7 this bug didn’t occur and if there might be an assumption from Max’s that other hosts share that might lead to crashes too.