When st opens a text with an emoji in it, it crashes. I sent a patch to alpine upstream to fix this in the library suckless tools use:
https://gitlab.alpinelinux.org/alpine/aports/-/merge_requests/22366
If alpine isnt willing to accept this patch, the pmOS people said they would. Posting here to track the progress on this.
I encountered this issue last night as well, took a while before I found this was the culprit. The problem was described upstream at suckless here: https://git.suckless.org/st/file/FAQ.html , with the bottom line being "it's an Xft bug not an st one". The Xft issue is here: https://gitlab.freedesktop.org/xorg/lib/libxft/-/merge_requests/1
Alpine merged your PR so all should be good in the next release and on edge.
Seems to be fixed for the subsection of emoji that are supported on the keyboard, but when an 'unknown' emoji is received, st still crashes in the same way.