Confirming @springwurm's report, exact same results here. Tested using Proton versions 5.09, 5.13, 3.16-9, and 4.11.
Switching to software renderer seems to workaround the Issue.
PROTON_FORCE_LARGE_ADDRESS_AWARE=0:x1 2020-05PROTON_NO_ESYNC=1:x1 2020-05PROTON_NO_FSYNC=1:x1 2020-05PROTON_USE_WINED3D=1:x1 2020-05
Compatibility Report
System Information
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Symptoms
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