I was trying to leave a comment on a friends page when I received this error message: Oh No! Please post the following error to the Problems and Bugs forum: not master
Please lock the problem seems to have fixed itself.
I'm getting this error as well. Just got it a moment ago. When I refreshed the user's profile and tried again, it worked, though.
I have also been getting this error a lot over the last two days... and it has been frustrating because they always seem to be long comments. I'm going to have start training myself to copy my comments before I submit them. :(
Slightly off topic but along the same glitch: I'm just getting a black bar across where the "Comment posted!" normally shows up.

Since there is already an existing thread for this, here, I am going to go ahead and lock this one. Feel free to repost your report in that thread.