This looks like a mistake. VST3_AUTO_MANIFEST FALSE should be passed to juce_add_plugin, and never target_compile_definitions. Adding it to the compile definitions like this is equivalent (in most compilers) to setting the preprocessor definitions like so:
VST3_AUTO_MANIFEST=1
FALSE=1
Setting FALSE=1 globally as a preprocessor definition will have unpredictable results.
Please try removing this line. If you really need to disable the manifest, add these arguments to the juce_add_plugin call, but this should be a temporary measure; it’s best to leave the manifest enabled unless there’s a specific issue you’re trying to avoid.