Mine did that and it gradually got more frequent.
Final straw is when it goes AWOL for long enough to fool the engine management computer that the engine is cold when it is really hot.
Next stage is rough running then it stops altogether
However, the solution (I found) was not that bad

, The sensor is on top of the right hand side of the engine below the tank and sticks vertically upwards.
Remove the side panel on the right (just pull it) and also the single tank retaining bolt behind it.
NOTE: The nut behind is NOT captive so get a finger in there to hold on to it!
Slide the tank gently backwards (easier when empty) and follow the wire leading out of the sensor, it has a 2 pin connector on top of the electrical gubbins in there near the left hand side.
On my bike this weekend, it was this connector which had corrosion in it.
Just pull the connector and clean the pins with an old toothbrush or similar and put it all back with a touch of WD40 - the temperature guage should now work.
Let us know how you get on,
Iain