Direto resistance not smooth on Zwift

[rozzer4314]

There are lots of variations of this problem on this Forum but posting to see if anyone has same issue.
When riding on Zwift. Not in ERG mode there are noticeable fluctuations in the resistance despite no gradient increases displayed on screen.
0% gradient can be shown on screen but resistance suddenly changes needing in some cases another 100plus watts to keep same speed.
Similarly when minor increases in gradient are displayed such as 0%-1% the resistance ramps up like I am climbing a 15% gradient. This sometimes only lasts for a couple of seconds before the trainer seems to sort itself out.
On my ride last night these resistance fluctuations were fairly noticeable for about the first 15-20minutes but then disappeared.
Zwift says it is not a zwift issue.
I am connecting via Bluetooth to an ipad.
Any answers would be greatly received as it’s annoying and ruining my indoor riding
Thanks