It causes strange problems when they aren't. This is what ensureOnMainRunLoop is for.
Created attachment 459909 [details] Patch
Committed r295080 (251175@main): <https://commits.webkit.org/251175@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 459909 [details].
<rdar://problem/94199423>
This was reverted in https://commits.webkit.org/251190@main due to causing https://bugs.webkit.org/show_bug.cgi?id=241190
Created attachment 459929 [details] Patch
Committed r295101 (251196@main): <https://commits.webkit.org/251196@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 459929 [details].