GIMP 3.2.x not recognizing rawtherapee plugin

[cjsmall]

I've used Gimp 2.10 and 3.0.8 and both have recognized the rawtherapee plug-in.  However, neither version 3.2.0 or 3.2.2 recognize it, although the proper files seem to be there.

I installed the extracted AppImage for all 3.x versions.  Here is a find search in 3.0.8 and 3.2.2 directories:

3.0.8:
49-> ffind file-rawtherapee
./usr/lib/x86_64-linux-gnu/gimp/3.0/plug-ins/file-rawtherapee
./usr/lib/x86_64-linux-gnu/gimp/3.0/plug-ins/file-rawtherapee/file-rawtherapee

3.2.2:
75-> ffind file-rawtherapee
./usr/lib/x86_64-linux-gnu/gimp/3.0/plug-ins/file-rawtherapee
./usr/lib/x86_64-linux-gnu/gimp/3.0/plug-ins/file-rawtherapee/file-rawtherapee

So the plugin is there.  From withing the respective programs I open:

Preferences -> Image Import & Export: Plug-In

3.0.8:
${gimp_plug_in_dir}/plug-ins/file-darktable/file-darktaple
${gimp_plug_in_dir}/plug-ins/file-raw-placeholderr/file-raw-placeholder
${gimp_plug_in_dir}/plug-ins/file-raw-rawtherapee/file-rawtherapee

3.2.2:
${gimp_plug_in_dir}/plug-ins/file-darktable/file-darktaple
${gimp_plug_in_dir}/plug-ins/file-raw-placeholderr/file-raw-placeholder

So the plug-in isn't listed.  However, I see no way to manually add a new plug-in to the list.  I never manually added it to other versions of GIMP, it just worked.

Any suggestions as to how I get this listed, and why the 3.2 series isn't loading this or picking it up from the previous 3.0.8 configuration?

Thanks.