I have issues with momentarily temperature spikes, but only above 250 °C. At and below 250 °C it's pretty solid.
I'm using Prusa MK3s+ with a E3D Revo upgrade.
I suspected connector issues as described in Random hot-end temperature spikes but in my case, the reported temperature spikes up, then compensates down - exactly opposite to what Space Faring Or Bust reported. Also, my issue happens only at specific temperatures. Connectors on both ends of a cable look good. I don't recall it happening earlier, on my old V6 hotend.
A side question is, are these even real? Or just a read error or a display artifact?
I cut the connector off and re-crimped it, but it didn't help, it looks exactly as it did before.