Strange export behavior with one VST

I made a simple 30 second loop to audition instruments. It consists of a scale of short notes, a scale of longer notes, and a series of triad and seventh chords, and this sequence is repeated in 3 different octaves. Looping through this is a quick way to preview how different instruments sound. I’ve had no problem with it on any of the stock instruments (e.g., Halion) or third-party VST’s (e.g., PianoTeq or Sakura) EXCEPT for one . . .

I have FL Studio installed on this same PC as Cubase . . .

… and it shows up as an instrument. I wanted to try out some of its “ooh” and “ahh” chorus sounds because there don’t seem to be any good stock ones in Cubase (please correct me if I’m wrong about that) , They PLAY OK in the loop but when I EXPORT them (File > Export > Audio Mixdown…) they’re all messed up in the MP3, with the notes out of order or overlapping, and when Cubase finishes the export the first note in the loop starts blaring out of my speakers and I have to turn it off in the FL Studio Editor!

How do I fix this and is it a problem I can expect in other third-party VST’s (e.g., Kontakt, which I expect to buy in the future)?

Thanks in advance.