If you have found burn marks and wear on the roller of your JetBlack Z1 PRO Fluid Trainer hopefully we can help you out.
Roller wearing is possible on your Fluid if when the bike was setup on the trainer there is insufficient tension between the roller and the tyre.
Once the tyre contacts the roller you should add a further 1.5 full turns of tension on the resistance unit (perhaps 2.5 if using a home trainer specific tyre as it has less grip - we strongly recommend only using normal tyres on our trainers).
The wear is caused by the tyre skidding on the roller. This causes the heat build-up and the friction build up will burn the roller.