remember, LED's are FAR from 100% efficient. that means heat. Not near as much as an incandescent, but still heat. Depending on construction and what LED's are used, figure 20-30% effficency. the rest is heat. And if they are using a simple dropping resistor to limit current, highly dependent on supply voltage. Good one use a constant current source that is independent of supply voltage over a wide supply voltage range.
I have strips on multiple florescent fixtures. Like any LED they will get warm to the touch. they should NOT get hot enough to burn or be uncomfortable but they will get reasonably warm.
