Recently, I asked my first question on retrocomputing.stackexchange.com .
I later attempted to ask a second question there, but when I clicked the "Post Your Question" button, a div element with a red background appeared, containing the error message, "You can only post once every 40 minutes." However, this was more than 60 minutes after my first question, so the error message did not seem to make sense.
It turned out that the error message was missing some pertinent information. It did not make clear that although the timeout only applied to the current site (e.g. retrocomputing.SE), the "40 minute" timer is measured from the user's most recent question asked anywhere on the Stack Exchange network. The absence of this information risks the user continuing to post elsewhere within the Stack Exchange network (as I had done), unaware that each time they do so, this would restart the timer and thereby extend the timeout arbitrarily, resulting in a negative user experience.
To fix the discrepancy between the error message and the actual behaviour, either the timeout code should be re-written to match the error message, or the error message should be re-written to correctly communicate to the user how the timeout works.