Two canonical tags in one of my websites head

Hello:

I’m having trouble with canonical tags. On a main page of a website I’m getting two canonical tags. The first one is controlled by the canonical url in the meta tags section and located just before the keywords meta name in the head. The second one, which I can’t seem to modify is located after the og metatags in the head. How do I fix this? Maybe a bug?

BTW, I don’t have any canonical tags set in the head template.