os-prober segmentation fault with latest grub release

After upgrading to grub 2:2.12.r212.g4dc616657-2, os-prober dies with a segmentation fault when running grub-mkconfig:

Generating grub configuration file ...
Found linux image: /boot/vmlinuz-linux
Found initrd image: /boot/initramfs-linux.img
Found fallback initrd image(s) in /boot:  initramfs-linux-fallback.img
Warning: os-prober will be executed to detect other bootable partitions.
Its output will be used to detect bootable binaries on them and create new boot entries.
/usr/lib/os-probes/50mounted-tests: line 72: 164878 Segmentation fault      grub-mount "$partition" "$tmpmnt" 2> /dev/null
Adding boot menu entry for UEFI Firmware Settings ...
done

This is a BIOS boot setup. I have a Windows 10 installation with a boot partition at /dev/sda3 and the main Windows partion, which is bitlocker-encrypted, at /dev/sda4. os-prober works with no issues under grub 2:2.12-3.