I am certainly not as experienced as many here and have all of six flight days under my belt. I too have the tilted gimbal issue when the P4A is turned off. However, because mine is new and the weather in Seattle is not conducive to much flying at this time of year, I decided to send my P4 in for a look see by DJI.
My gimbal has performed flawlessly during flight and has been very responsive to all flight moves, tests, videos, photos, etc. On one flight I did get the gimbal motor overload error and then the gimbal calibration failed three times but finally did calibrate as expected. Subsequent flights revealed no issues except the sagging gimbal when the unit is turned off. DJI support stated this was a "known issue" and many here advise that there is no issue but due to the newness and full warranty I decided to send it in after trying multiple Firmware releases.
Today, DJI sent a message stating they were going to spend two hours and replace the gimbal. This would indicate it is more than a "known issue" but rather something physical that was in error with my unit.
It would have cost $829 if I were paying but, of course, it is 100% covered by warranty. Of course, this could certainly be a one-off situation but if you have a new unit with warranty coverage, it might make sense to send it to DJI for an examination while your warranty is in effect.