First thing I would do is look at the properties of each waypoint and see what the gimbal pitch is supposed to be. See if they make sense and that the gimbal was, in fact, not pointing where the waypoint says. This will rule out "programming error." (BTW, if you make changes to a WP in terms of position or height you need to punch "focus POI" again to force it to recalculate. I doubt that's your issue here though.)
There DOES seem to be a condition where gimbal adjustments will not be executed after a reconnect even though they are supposed to. In my case it involved a spurious "mission ended" call out. I contacted Litchi about this and this was their reply:
"The mission ended is a bug from the DJI dev kit which we already reported to DJI. Litchi will announce “mission ended” whenever it is told that the mission has ended, which wasn’t the case here. It should be rare however as we have not received a lot of similar reports, the reports we did receive in the past were all for the P3 Standard however and would happen when signal is lost (even if just for a split second). It is possible that after the DJI dev kit reports that the mission has ended, it will also stop reporting other changes to Litchi such as when the drone reaches a waypoint for example, this kind of information is required for the gimbal control to work.
We’re not sure when (or if) DJI will fix this bug, we reported it a long time ago for the P3 Standard."
Here is the whole thread on my issue:
Mission Completed - Not