Friendship behavior change after female Bengal was fixed.

Ok it rescue male cat, Geppetto, is 2yrs old and was fixed around 6months old. We brought in a female Bengal, lady, 3 months ago and they became good friends one week in. Always play fighting, hanging around each other, lady licking his face. Never a problem. Well after bring lady back from being fixed, Geppetto doesn't seem want to do anything with her. Several times when she walks by, hr makes a low growl and will hiss. What could cause such a dramatic change? We could only think of lady not being in heat anymore but didn't think that would be a cause. What do you think?

Take in it has only been a few days and that could change, but it just seems so odd.

She smells different from being at the vet and he doesn't recognize her. They'll go back to normal soon! You can rub a blanket that smells like him on her to help.

We thought that too but didn't think she smell like it, we'll give it a shot!

Cats know each other by scent. I have this problem between my 2 after almost every vet visit.  Lady smells like the vets office, she's had surgery and he's sure to pick all that up. They can smell things we cannot.  

Rubbing them both with the same sock/blanket/towel can help.  Sometimes a dab of vanilla at the base of each of their necks can help too.  My girls don't really like that though. I have wondered if they think the vanilla is too strong of a scent.  

Hopefully they will be back to normal soon.  My my 2; 3 days is about average.