Playback starts after file export

Hi gurus,
I have a strange thing going on with Nuendo 10.
After a mix export, the dialogue closes but the project starts playing automatically.
Can anyone enlighten me?

Update - this seems to occur ONLY when Wavelab 10 is also open. Windows 10. Such strangeness.

I happens to me every time. Nuendo 10 and Nuendo 11.

It’s really annoying.