Yes this is a bug. I've logged it on the Audacity bug tracker.
As a workaround, the plug-in, or a copy of the plug-in can be placed into:
32-bit Windows:
C:\\Program Files\\Audacity
or
64-bit Windows:
C:\\Program Files (x86)\\Audacity
Yes this is a bug. I've logged it on the Audacity bug tracker.
Do you ever go back and edit them? If not then you could save even more space by saving only the exported mix.