It's possible it's new dose wokiness which is seen in cycles 2 or 3 of a new dose.
"Many cats will occasionally react to an increased dose with increased BGs - within the first 2 to 3 days after an increase, usually lasting for less than 24 hours. Nobody really knows what the reason for this phenomenon is (perhaps a "panicky liver"?) - hold the dose and ignore the fluctuations." http://www.tillydiabetes.net/en_6_protocol2.htm. Here in the Lantus, Levemir, and Biosimilars Insulin Support Group (ISG), we've affectionately dubbed this unexplained phenomenon "New Dose Wonkiness" (NDW).
A cat's insulin needs go up and down. And with it their numbers. Our job is to follow the numbers and change the dose accordingly. Give her a little more time