I have the 'fox' form. As far as I can tell, there are 3
outcomes from using the 'jump' skill:
1) You successfully jump
2) You aren't allowed to jump in this terrain (and see an
appropriate message)
3) Your attempt to jump fails whatever the skill check is (and
see a different message)

The jump skill says that you can use it to escape combat as
long as you are outdoors. However, there is a skill check, and
if you are in combat, it's possible that you fail the attempt
to jump.

My expectation:
When in combat, in a room that it is possible to jump from,
and I fail the skill check, I expect the skill failure message
from outcome [3] above. (It's been a while since I had this
happen, but I think the message is just something like,
"you fail to jump")

What actually happens:
When in combat, in a room that it is possible to jump from,
and I fail the skill check, the error message from outcome [2]
above is shown. Specifically, it says "You cannot jump in
that direction."

Commentary:
This is a problem for a few reasons, the biggest being that
the incorrect error message leads one to believe that jump
simply doesn't work the way that the helpfile says. In fact, I
was originally writing this bug report about the jump skill
not allowing one to use it while fighting, but apparently it
just has a low chance of success, and I actually succeeded for
the first time while collecting the log below.

Your direction chosen doesn't matter during combat.

In combat, your jump is a random direction.

Hence what you're seeing.