Some of them were even a little bit funny

I had that happen earlier, or so I thought. I had a notification that someone replied to one of my comments. I went to the page and my original comment was gone. I thought that maybe he deleted it somehow and I was ready to rip him a new one. I went back a few minutes later and my comment was there.

imgflip must be glitching. It's happened several times and like you said, comes back later.

yeah same. post a comment and sometimes it won't appear for a little while

So they ARE appearing? This was doing my head in today.

Give them time, they do reappear.

I wouldn't worry about it.