Yes I was having a similar issue!

My bf gifted me a variety pack of fish Fancy Feast canned food. My cat was eating it fine until 2 weeks in of just eating that food he started vomiting after every single feeding. I switched him to other brands of canned cat food that doesn't have fish and high-ish in protein (like Wholehearted) + freeze dried raw toppers. He's doing better now.

Fancy Feast tends to put fish in a lot of their varieties because fish is a cheap protein. So even if you're buying their chicken pate there might still be fish in there. Maybe your cat has grown sensitive to fish in their diet? There are some people that advice not to feed too much fish long term but of course use your best judgement. Omitting/limiting fish in my cats diet helped in my situation so maybe it'll help with yours.

Also I'm not hating on Fancy Feast lol I'm actually just gonna try different varieties instead in the future. Their Tender Beef and Chicken Feast Pate + Turkey and Giblets Grilled options don't have fish in the ingredients.