Found by Exenon & reported on the Discord.

Steps to reproduce:

• Add ZynAddSubFX to Song Editor
• In the instrument settings, increase the pitch range and drag the pitch knob up or down until notes played are noticeably higher/lower pitched
• Place a long note for ZynAddSubFX to play
• Export the track

You should notice the exported track plays a lower pitched note. In LMMS, the Zyn instrument will now also play at a lower pitch as well.

According to Exenon's report, the pitch knob will visually reset to zero as well, and they have to drag it back up. For me, the pitch knob stays visually correct but has no effect. If I wiggle it a tad with scroll up and then down, it comes back into effect and Zyn will play at the correct higher pitch again.

This happens in 1.2.0-RC2. Exenon is on Windows 7 32 bit, I'm on Windows 10 64 bit.

Update: Creating an automation track that changes the pitch makes it work as well. This only has to happen once, for example: