So, syscall 372 on x86-32 is recvmsg. Googling says this is a Chromium bug, it uses that syscall indirectly but doesn't allow it in the sandbox setup; only reported once for this particular syscall, but many reports for others.
I guess they very rarely test 32-bit nowadays. Unless you want to patch and build chromium yourself, moving to 64-bit may be the only remaining option.