https://www.legacysurvey.org//viewer/?ra=82.9300&dec=-65.7527&layer=ls-dr10&zoom=16&const
I can see whatever this is in almost all the single exposures albeit somewhat dim in some. So I dont believe it is a cosmic ray hit or artifact. I also looked at it on Aladin Lite DESI Legacy DR10. Its color is similar to the green shown in nearby stars.