Issues with simcoders REP for V35B in Xplane 11.10

Hi,

I have taken the plunge and bought in to the REP pack for the V35B as indicated in post title. However I'm having issues with the performance of the V35B in XPlane with the REP pack enabled.

On the ground, once the engine is started, I see the RPM spike (-200rpm) and the plane "twitches" to the left around every 10 seconds with a small but visible rotation and resettling of the aircraft. I get the grey message bar "flash" for one frame, so I can't read what it says, but I can see it's trying to tell me something. To me it looks like the REP lua engine(?) is somehow getting out of sync or freezing momentarily, throws a flight model error or failure, and on the next frame it attempts to catch up, with the corresponding increase in RPM back to the current set RPM. However that doesn't explain the aircraft trying to rotate left..

This then manifests in the aircraft being uncontrollable on the during taxi or takeoff roll. During taxi it keeps pulling very lightly to the left, and on the takeoff roll, it will veer left with no amount of rudder or toe-brake being able to keep it on the runway. It'll end in a spin if I keep trying to correct it, and I have to just ignore the faulty takeoff and pull up once I have speed. Weather is clear, no wind.

Once in the air I don't notice much, except the grey bar at the top flashing momentarily for a frame, every 10 seconds or so.

I've tried increasing the calculations per frame in Xplane general settings, and also reducing the graphics settings to see if that helped. I've killed all background programs not required, and none of the above makes any difference. Otherwise I have a respectable pc (i7-7700K, 16GB ram, GTX 980) so I'm not leaning towards performance as an issue. However feel free to prove me wrong :)

I have none of these issues if I disable to REP pack and fly the standard Carenado V35B.

Any help or suggestions on how to isolate the source of the issue is much appreciated. I have high hopes as I don't see other people complaining about their products and seem to have a very good reputation in the community.

Email sent to simcoders support, and awaiting a reply, but thought I would also ask here as there appears to be some knowledgeable people who might have had a similar experience.

Thanks in advance.