Did you activate it?

Every couple of pulses there's a check for aggros to attack people. If someone of a certain level or lower is standing there, the aggro attacks. Gentlewalk gets taken into account each time that's checked. Unfortunately, the way it seems coded, it checks your skill at gentlewalk. So with 75% skill at gentlewalk, you might make 3 checks of the mob not attacking you, but then on the fourth check the mob attacks you. Since the checks come so rapidly, all this happens very quickly, thus it seems like gentlewalk isn't working.

Fortunately, gentlewalk is easy to perfect, and once perfected it works like a charm.

Perhaps something broke it, because it really has worked quite well
lately. Something might have gotten altered in the ranger revamp.

If you could post on the Bug Board that it has never worked for you,
your level and the specific mobs you're walking past, that would be
helpful. Try to keep the emotional stuff (if you can) to a minimum
since it is just more text for them to ignore while trying to solve
the problem.

Once it is working for you, I think you'll find it pretty handy.

Qaledus

It gets better with skill percentage.

Additionally, mobs that attack via a prog will still attack you. It only works on "normal" aggro mobs.

One useful mob it works on: inn bouncers.

I suspect it also works on conjurer pets, nightwalkers and city guards (when you're wanted), but I haven't tried any of those.

My last thief had no problems with perfected Gentlewalk, but he visited only low level areas.