I've read somewhere that rotaries don't like engine breaking, i've search but only found one other mention of this fact. Also without an explanation.

Is this someone who misread something about 'rotary', 'engine' and 'breaking' or just another endless AST removal/replacement, 30sec/10min warmup discussion?

I can't think of a plausible theory way this would bad for the engine.

 

it's pretty bad when you break the engine

now engine braking, not so much