A heatsink transfers heat from something hot,and helps dissipate it. The LED lights in your spa and mine utilize 1 of those. It sounds like yours is defective,esp if your lights are out of synch.
The LED control button shouldn't be "hot". It should be slightly warm,and that's it.
As far as a safety hazard,I wouldn't sweat it as far as rushing to get it fixed etc. I would let your dealer know about your problem,and schedule a repair. Tell him/her to bring out what's needed to repair/replace the heatsink issue and the spaglo lighting being out of synch.
I would rush it if,your warranty is close to expired. I don't recall what the warranty is as far as the spaglo.