I have recently updated to ver. 2.8.6 and since then I have not been able to insert tags.
Another problem is that in the control panel, I am not able to change screen options.
Also, when I insert a picture I cannot edit it.
Have the same problem, also immediately after doing the automatic upgrade to 2.8.6.
It’s sort of wierd, because i have a plugin that suggests tags, and i can add tags that way, but when i enter tags manually, it doesn’t add them, and when i click on the link to add from the list of most common tags, it does nothing.