That line was probably a Starlink launch spreading out, what’s more surprising to me is that in what you linked the image is from Hubble. I didn’t think space telescopes would have the same issue ground based telescopes did.

The bright line is Starlink satellites immediately after deployment.

Starlink satellites do have stealth features to make them less bright, but those are only active in normal operational mode. Immediately after deployment and while dodging space debris, they are more visible.