Please refer to the clone to see the description and history.
This bug is still there in Build 20210124
The code file is totally changed since the patch mentioned in the old ticket even renamed.
The problem seems to be caused by not putting quotation marks around %1 when creating Application/shell/open/command registry entry.
One thing strange is that fixing registry entry by hand won't change handler program behavior until you change the default handler to something else and back.