We have an Aqua Magic Aurora toilet in our 5th and it has given flush problems off and on since it was new. I've replaced the water valve once and put seal kits in it three times. It has started leaki...
I had a dometic in a born free it was a pain, bought a complete rebuild kit , sat on the ground and went to it, its never failed after that. I think that the assemblers get things out of wak . sometimes and just send them down the line.