This issue seems to be happening only since version 5.2 of Juce. I try to compile Win32 plugin for my 32 bit test host DAW. This 32 bit host cannot detect this plugin however another 64 bit host detects it and loads without any problem. I made sure all settings in Projucer and then Microsoft Visual 15.4.1 say WIN32 or x86.
I didn’t have this issue in Juce 5.1. Do you run into the same problem?