Hello
On freshly installed Mint 22, Syncthing package 1.27.2~ds4-1ubuntu0.24.04.1 syncthing does not restart after laptop suspends and restores, the process is killed so -HUP from /lib/systemd/system/syncthing-resume.service does nothing.
Fix (More like a workaround / bodge) … change line ExecStart in /lib/systemd/system/syncthing-resume.service to …
ExecStart=/usr/bin/syncthing serve --no-browser --no-restart --logflags=0
It works but does not address the real issue of syncthing process dieing.