Did you move the Aloes into a more sunny spot? You probably also did not really know which side was facing south before given that they were on the ground. I could just be sun burn. It looks a little weird and given that it seems to affect the newer leaves in the core and not so much the older outer ones gives me some pause, but it does not look like the leaf is getting mushy.
Is the soil well draining and how often do you water them?
BTW. Your plants are definitely Aloes, but given how they look are almost certainly not actual Aloe vera, which is a specific Aloe. Aloe vera is often used by people to indicate any kind of Aloe, but technically that is not correct.
Turbosaurus said:Ditto, its a sunburn.
Plants are a lot like people- they need a bit of a base tan, lol, before they can tolerate full all day sun- I am not sure what summers are like in Malta, but in NY I gradually move them around this time of year into sunnier spots and I always make a mistake where some plant gets a bit of a burn- but its worth it. An aloe slowly acclimated to full sun over 2-3 weeks will tend to do better than one I leave in part shade.