stray

not close together in time

isolated instances of rebellion

a few stray crumbs

(of an animal) having no home or having wandered away from home

a stray calf

a stray dog

an animal that has strayed (especially a domestic animal)

lose clarity or turn aside especially from the main subject of attention or course of argument in writing, thinking, or speaking

She always digresses when telling a story

her mind wanders

move about aimlessly or without any destination, often in search of food or employment

The gypsies roamed the woods

roving vagabonds

wander from a direct course or at random

The child strayed from the path and her parents lost sight of her

don't drift from the set course