There is asymmetric load out on last 3 pictures. In picture 2 and 3 only one Pl 12 training round on right wing.
In the last picture one Pl 10 and Pl 12 is carried on non linear pylons.
Anyone can shed some light on the reason.
You don’t need a full weapons load for training.
The PL12 photos were most likely from sorties training BVR only, in which case there is no benefit in carrying more than one PL12 training round, while carrying more not only require far more training rounds to be bought across the whole fleet if such practice was standardised; it will also increase drag resulting in higher fuel costs and/or less training flight time for the pilot.
Similar deal with the PL10 and PL12 load out. That is more likely a more comprehensive air combat training exercise involving BVR as well as WVR, in which case one training round for each is needed and no more.
For live rounds, you also have useful life to consider, as live missiles are only good for so many flights hours.
Hanging excessive numbers of live rounds during training/routine patrol will just deplete those hours needlessly quickly.