If you don’t see your own posts highlighted, then you are logged on with a different user id from that which was used to post the original alert or spot.
What follows is a guess: It used to be that you could (accidentally) log on with a user id that had a space embedded or before the callsign letters. Internally, sotawatch used to validate that user and find it matched (by removing spaces before the comparison) but did not remove (the spaces) from the callsign in the actual post. So when you want to edit it, you have to log on with the same leading or trailing space. I thought that problem had been fixed long ago, but just in case, try with your home computer using the website rather than sotagoat.
73 Andrew VK1DA/VK2UH
Edit: I see you are using sotl.as to post spots, so the above guess is probably not relevant.