Hello aspirant,

Stray Round Is that round of counseling which generally happens after Mop-Up Round. It is generally conducted by state counseling authorities and is generally conducted by state colleges to fill up any stray vacancy which may arise after Mop-Up round of state counseling.  The stray round is done for deemed, central universities and ESIC colleges .
You can get the detailed information from given link:-
https://medicine.careers360.com/articles/neet-counselling

All the best