Nuendo MIDI clock to Ableton doesnt sync

I have Nuendo 13 and Ableton Live 12 running on the same machine.

I have set Nuendo to send MIDI clock with internal MIDI connection. Ableton receives MIDI clock and is set to ext. sync

When the tempo in nuendo is 120bpm and the transport is stopped, Ableton shows ~120bpm, but when I start the transport (press play button) ableton then jumps to about 130bpm.

Tempo track is Off

what could be causing this.

Ive tried three different internal MIDI drivers
-Loopbe
-Akai internal MIDI (MPC)
-IPMIDI nerds.de

all show same behavior

Try disabling any MIDI inputs to Nuendo. Does that help?