Will a night of co-sleeping here and there undo sleep training?

Our girl is nearly 6 months and I'd say she is fully sleep trained. We now put her down at night and she just falls asleep- no fussing, no crying, no paci. She does still wake to eat 1-2 times per night, but goes right back to sleep after.

She also occasionally has a rough night here and there due to teething, milestones, a weird nap day, etc. Most of the time, we work through it with her remaining in her crib and it's not too bad. However, every once in a while, there's a night where things have been especially rough and I know co-sleeping (using the safe 7) would mean more rest for both of us.

Would doing that every once in a while totally undo the progress we've made with sleep training?