It must have been fixed and regressed again. In my local build, I see a hang, with "double free or corruption" in the log. In Proton Experimental, it shows up for a second and then crashes. In Proton 10.0-2 (beta), it wo...
If I'm not mistaken, I tested this again on a newer Proton and didn't get the memory leak. I'll make sure to test again here in the coming days, though.