Page not found in snippet error for translated pages

If you have a translated page with a custom slug, when you share that page to Facebook or other social network, you get a “Page not found” error.

I don’t know where the problem lies, but I suspect it has to do with the fact that the page has a different slug and the redirect between an original page and its translations is done by Grav.

Has anyone any idea how to solve this? And/or how to better describe the issue, so that I can open a bug report?