Inconsistent cadence reading with Wattbike Atom

Have been using Zwift on my ipad with a Wattbike Atom for about a year now mostly without any problems. However, in the last week in three of my workouts the cadence reading keeps randomly jumping up or down by about 20-30 rpm every 3 or 4 seconds. This has a knock on effect on the resistance when using ERG mode particularly when the the RPM reading drops as the resistance increases accordingly to match the required watts. This quickly becomes very tiring when doing workout intervals at threshhold because the resistance suddenly jumps equivalent to about 100 watts.

Anyone else having this issue? It appears to be only related to Zwift because it doesn’t happen when i’m using the Wattbike app or on Sufferfest.

I re-installed Zwift on the ipad but that didn’t seem to make any difference, any suggestions to fix the issue?