Nicehash tends to bounce your miners around quite a bit due to the very nature of their service.
I'd not worry about hashrates bouncing a fair bit.
Also, the chart is PROFITABILITY not hashrate - and that bounces around even more as folks start new orders, have orders run out, change payment on existing orders, etc.
Good point thanks for that.
However let me also clarify that i was also monitoring hash rates and they were jumping from 28MH to 10MH every now and then. Found out that it could have been due to high GPU temps. I tried increasing fan speeds and air circulation/placement of GPUs and the fluctuating hash rates decreased. They seem to be fixed at a constant value now.