That is strange..
Just to be sure of the details, I do not have After Effects 2020 installed on my OSX system at the moment, are you putting it in:
"Applications/Adobe After Effects 2020/Plug-ins" (with the `-`?)
You mention "Applications/Adobe After Effects 2020/Plugins" and I have only recalled it with the "-" and want to be explicit that there isn't a discrepancy there.
Also, are you a previous user of this plugin? Has it worked before for you on this system until After Effects 2020? It might take some time for me to be able to recreate these circumstances on my end.