I'm glad to hear Logan is feeling better- and that his X-ray shows no stones!
Tigris had an attack of that iFLUTD (I remember the i meaning idiopathic because there is no known reason to it) 3 years ago during the Christmas days. It came back one time after 2 months and then never again. Hope it is the same with Logan kitty
Of course you'll watch Logan just as we watch Tigris now- but there is a good chance he'll stay healthy.