From the look of the leaf in picture 1 it looks like leaf scortch
This is where a droplet of water has sat on the leaf and sunlight has
burnt the leaft - a bit like a magnifying glass. Can occur from
condensation dripping onto the leaves or when watering spash onto the
leaves.
Generally if it is a pest you see the problem on top, if you turn the
leaft over the beasty can be found underneath.
If it is a disease generally it is widespread, rather than localised.
It looks alarming to you but in relation to the size of the plant it
isn't much. If the motling does spread, you can always remove the
affected leaf and dispose of it ( not onto the compost heap)
Regards
Clifford
Bawtry, Doncaster, South Yorkshire