@Christo37433424 Your logs or even database may indicate better where it came from, but most likely it's a malformed received webmention or one without data. I've seen one or two in the wild, but unsure what may have caused it.
I thought it might be from me, https://boffosocko.com/2018/09/04/my-first-experience-with-indieweb-christopher-tomilson/ but the dates don't align.