This lock out usually didnt happen on the "first try" (for me, anyhow).
Prior to the server to APF timing out, i would get a page showing a 400 error that was occurring. It was almost like the 3 strike rule. On the third try, the mulit-colored wheel would spin (i'm a mac guy), and after 30+ seconds, I would get a screen from any browser I tried, saying something to the effect that "the server you are trying to reach may be busy right now, check your network connection, firewall issues etc and please try again later."
But it isnt only cut and paste that causes the issue. One one occasion, a fellow member was asking me to edit some info from a very long post he had written. Even trying to do that (again just for me) caused the issue of the error window to appear when i tried to Preview the amended post. I gave up after 2 tries, obviously.
Another time, it was a post that, I think, was using too many characters (letters). I got the same error window.. so i had to reduce what i had wanted to write and post.
We are trying to figure it out, Matt. Hang in there, buddy.
It seems quite random, tho the cut and paste issue is one of them. I also was wondering if cutting a pasting an actual url address could trigger this error.