This is a symptom of the camera not being able to keep up with the settings while writing images to the SD card. You should be seeing "Photo Error" pop up when it happens.
We recommend the 2.5 seconds per image setting even if you think your card is faster.
Your most recent flights (from the 14th) look OK while your flights from the 11th do not.
When doing Terrain Aware flight some extra waypoints are added to handle the flight altitude adjustment. When a flight segment ends the app attempts to take an image even if it wasn't time to distance-wise. Some of these images can be dropped since they were attempted on a short distance. You have a couple of those but they won't be a big deal in your overlap consistency.
Are you SD cards freshly formatted?
What is your SD Card Speed Class Rating set to in the Map Pilot Settings?