I had exactly the same problem and found a fix !!
I noticed that this problem was only occurring when I was running the evernote app on my Mac AND was connected to a VPN. The problem was further obscured by the fact that some VPN connections did not produce this problem. However, when the problem did occur and I switched the VPN off or moved to a less 'conspicuous" VPN server :) , the problem went away instantly and I could annotate all previous images that I couldn't before.
Hope this helps!!