Hello,
I just spotted this code which looks like a leak to me:
Inside juce_mac_CoreMidi.cpp, setUniqueIdForMidiPort:
CFURLRef bundleURL = CFURLCreateWithFileSystemPath (kCFAllocatorDefault, appBundle.getFullPathName().toCFString(), kCFURLPOSIXPathStyle, true);
According to juce_String.h the return value of String::toCFString() must be released via CFRelease().
Searching on toCFString() I see suspicious usage in juce_AudioUnitPluginFormat.mm, getValueForText(), line 431 as well.
Thanks for taking a look!
Rob