Hot end heat won't stabalise

Greetings,

I had to replace my hot end and am now seeing the nozzle temp fluctuate between 208 and 221 constantly (printing at 210).

Even when I start a new print, it won’t start until I disconnect the fan, let it settle (kind of) let the print start and then reconnect the fan.

I have tried 2 different hot ends with new sensors and it didn’t make any difference.

Prints are fine once it gets going.

Cheers