I have noticed three times since I have owned a P4,  Occasionally when up a hundred feet or more that when I try to come down it just don't want to drop.  it will go down but very slowly.
One day there was a mild 2 or 3 mph offshore wind but for the most part is was not a windy day. (not even a couple hundred feet in the air.) The drone will sit stationary, (not like its fighting against a wind to maintain position.) And it only happens for a minute or so then the thing flys like normal again.
I have had 2 different P4s and noticed it on the new one too.
Has anyone else experienced this? Is there a fix? It is very discerning when you on full down and the drone is losing a half a foot a second or less. (I literally to turn mine into a big spiral dive to get it to come down yesterday...full down from 180 feet and it was just taking forever.)

Hi Mastertech, may we know have you tried to calibrate IMU and the vision positioning system?
Or installed gimbal guard?
The firmware is up to date, right?

I did not try to calibrate anything, It is a refurbished unit (or new?) that I just got back from the DJI repair center in L.A. California.   When I plugged it and connected the remote all was showing everything working a-ok. all of the compass and gps and sensors said all good.  I went thru the whole list and set it up for flight mode p. ( I always leave everything for safe flight on at all times. I'm a newer drone pilot, better on and not needed then off and crashing into things.
What's funny is it doesn't happen all of the time.. one minute its flying perfect, up and down both respond fine, then all of a sudden it just wont go down at the normal rate (goes up just fine). It happened last flight at just under 200 feet.. close to me as I could clearly see the drone right in front of me.  I just downloaded the flight data if anyone wants to look at it.  I show the down stick on full down for 10-30 seconds at a time but the drone would only lose about 1 foot a second if even...barely coming down. I had to put it into a spiralling loop to lose altitude. its the last flight on 23/10/2016  
just watch the height, at about 230 feet you will see the full down stick with slow or no downward response from the drone. I was 220 feet from the drone with no obstructions or radio interference that I could detect on my screen.
I thought those gimble guards were not good so no I don't use one.
Please let me know if you find anything or have any ideas.

Try calibrating the RC, it's an easy job that takes a couple of minutes or so.

It would probably be good working practice to do all five calibrations if not already done.

IMU, Gimbal, Sensors, RC & Compass.

Hi Mastertech, please do calibration, and then check again.
If still the same case, please sync your flight records through APP, provide us your DJI account (E-mail address), we will help you check it.
Besides, may I know what is your case number for previous RMA?

I've seen the same thing a couple of times too.  Not so severe but still pretty much not in a hurry to come down.  Mine will do that if above 50m.  It will then slowly start to come down and then after 2 - 3 seconds pick up speed....

Ok so Im glad Im not the only one who's seen this. It worries me because im pretty sure I had a problem like that one flight before mine fell from the sky.
My case number was   CAS-273316-V2Q4P6   they looked at it and basically just replaced it. (Id love to know why it stopped flying, I live in Oceanside Ca. There a lot of people and expensive property Id prefer not to damage.)
It rained yesterday So I will go out after work and recalibrate everything that can be calibrated.  (When prepping to fly does it not show if there is a problem?  says right across the top gps and compass...when there are errors or interferance you get all kinds of warnings.)