Pounce Treats vomit

I have a little tortie named Motley who loves Pounce treats. When we
got her over a year ago she was very shy, wouldn't sit on a lap or
allow anyone to touch her, I softened her up by enticing her onto my
lap with Pounce treats.

She has mellowed considerably but still expects a nightly dose of
treats. Unfortunately, she has recently started vomiting within
minutes of having her treats. She doesn't vomit otherwise.

Any idea why the sudden sensitivity?

I hate to stop giving her the treats, but I hate cleaning up after her
too.