Why does meld get stuck on my remote 3-way comparison?

I'm running a 3-way merge using meld (via git mdiff actually) - on a remote machine. My own machine is Windows 10, and the remote machine is Devuan GNU/Linux Chimaera. While the meld window does come up with the 3 files, there's a "loading" kind of UI indication on the meld toolbar, and the file contents is grayed out. After 5 minutes - nothing has changed. I should mention the files are not very long - under 1,500 lines. On the Windows machine, I'm using mobaxterm with its X server. Why is this happening?