I think this is what electric ovens do. They warm up untl they reach the set temperature then the thermostat switch opens and the flow of electricity ceases. The oven slowly cools down a little bit. Then the thermostat switch makes and the heating process begins again.
Anyway - this is how my oven behaves and all the other ovens that I've owned. Just one light that says, "I am warming up." if it's not on then the oven is not warming up - i.e. at - or close to - the set temperature
The dimming and brightening of the display may be due to stray light from the other indicators.
The acid test is - is it cooking OK?
Good luck...
Peccavi
November 2012