four year old beagle mix who never once counter surfed in three and a half years has suddenly started doing it nightly for the last three months and i cannot for the life of me figure out what changed

Hattie is a 28lb beagle mix we adopted from a county shelter at six months old, shes now just shy of four and a half and she has lived with us in the same kitchen for the entire time. for the first three and a half years she did not touch the counter once. not when we left a roast on it for two hours one thanksgiving, not when we put her dinner on the counter while we washed the bowl, not even the time we left an entire stick of butter sitting out overnight by accident. she is a beagle, the not-counter-surfing was honestly one of the most surprising things about her, every other beagle owner we know is amazed.

three months ago that broke. i came downstairs at 6am to find a stick of cooking butter chewed up on the floor and assumed someone had left it within her reach. a week later, half a loaf of sourdough that had been on the back of the counter, gone. since then its been escalating, shes counter surfing pretty much every night, and at this point its anything we leave out, oils, fruit, a sleeve of crackers, twice now a stick of unsalted butter just chewed and abandoned. we have basically had to start treating the kitchen like a baby proofed space which is wild for a dog who lived here for three and a half years like a totally trustworthy adult.

what we have ruled out. no diet change, shes been on the same kibble for two years. no household change, no kids no new pets no new people no recent move. no obvious medical issue, she had her annual in march and bloodwork was clean. her routine is the same, two walks a day, midday yard time, evening play. shes not losing weight (actually shes up half a pound which we attribute to the literal butter). shes the same dog in every other way, she still sleeps through the night, still plays normally, still listens to her recall and her sit.

my question for the people who have walked through a sudden onset behavior change in an adult dog like this. what turned out to actually be driving it for you, and how did you figure out the trigger when nothing in the household had visibly changed. i feel like i am missing something obvious and i am genuinely stumped