I've managed to reticulate Tri-X sheet film a couple of times using PMK and fix or wash water that was too cold. I think the alkalinity of the developer swells the emulsion a great deal, making it more vulnerable to temperature variations.
I had never encountered reticulation in my previous 20+ years of darkroom work. I'm now much more careful about maintaining consistent processing temperatures across all solutions.
I suppose it depends on what definition is placed on a "few degrees" but my experience largely reflects the above statement. What I am going to say happened to me only once and it was HP5+ 35mm film. In my early days of darkroom work at a nightschool darkroom with a crush of other students all trying to use the dedicated film processing area which had normal lighting I went out into the safe-lit printing darkroom area to wash the film. Big mistake. I couldn't make out the hot from the cold taps( which delivered tepid water - not cold water) and started to pour hot water into the film. After a short time, less than a minute something made me feel the temp of the water and it was really warm on my hand which must have made it more than 10 degrees C warmer than the cold water at least. I never tested the difference but I suspect it was a lot more than 10 degrees C
Result was no damage at all. OK there might have been if I had continued long enough but I concluded that HP5+ had to be pretty tough stuff to withstand the sudden assault it received.