Just realized something else...
Do you have a monitor connected to the HDMI output? That will also disable touch tracking mode. (Spot focus will still work on the camera touchscreen, even though no image will display there while recording).
The detailed explanation definitely explains why smaller apertures have a longer delay than a wider one. However I am not able to use the focusing explanation to answer why the camera in Auto mode or with the Focus Area set to Wide do not have a noticeable delay other than the expected TTL delay.
Have I missed something?
Basically the flash only fires, once proper focus has been acquired.
The delay in releasing the flash is a direct consequence of the delayed focus acqusition.
In a "flash use" situation, the lighting conditions are probably rather low, otherwise you wouldn't be using a flash in the first place. In low light conditions, the camera cannot use contrast AF, because contrast is also too low.
So it has to use PDAF, which uses kind of a range finding mechanism, which employs the evaluati