TMZ obtained a Milton PD report in which officers say they slapped Kroy with a citation Saturday due to a neighbor's complaint about his dog, Stone, getting loose and allegedly terrorizing a neighbor.

According to the docs, the neighbor called police after spotting the dog running free in the neighborhood, and claimed Stone had been "aggressive" toward her.

Stone eventually made it back home to Kroy, who spoke to responding officers about how his 3-year-old Cane Corso -- a type of mastiff -- got out in the first place.

Kim's estranged husband explained his son was supposed to be watching Stone, but the dog must have gotten away from the youngster.

While the Biermanns do have a gate that's supposed to keep Stone on their property, Kroy told cops it was broken, and in the open position. Kroy said he'd found the dog on the sidewalk in front of their house, and not down the street.

Nevertheless, cops found enough from their investigation to hit Kroy with a citation over it.

Of course, this isn't the first time cops have been called over Stone's behavior. TMZ broke the story in November ... a woman called the cops after she saw Stone off leash, and claimed the dog "almost attacked her kids" a month earlier.

Neighbors had previously chatted about Kim and Kroy's pups in a Facebook group, where they alleged the couple often leaves the gate open.

Still, this dog drama is the least worrisome thing plaguing Kim and Kroy ... as the estranged duo is facing everything from a looming foreclosure on their home to lawsuits over debts.