editing posts not allowed?

[airflow]

(20-01-2016 14:29)simoncn Wrote:  This should work. I had the same problem doing this with quick edit a few days ago but it worked with full edit. I will try editing this post now to see what happens.

Quick edit: this worked.

Full edit: this worked.

I tried editing posts with different methods and different browsers, but the result is the same (see screenshot). Perhaps the reason can be spot in the logs of the webserver? Perhaps the post is too old to be edited?

PS: I could edit *this* post, but not the other one! ;-)