The blade is not eroded, a close look at the metal on the leading edge will show that. It does seem to have been flown in heavy rain earlier in its life with fresh paint which is why the paint is flaked off as it is. That is quite often seen.
Also very often seen is bug damage like this, even with just one day at Low Level it can be like this and a real pain to clean.
There are plenty of hypothesis around regarding dry air - moist seaside air etc etc that suggest the commencements of de bonding. In this photograph I believe there is a lot more to the story.
Have a look at the damage to the skin above the rear spar area and what looks like warping of the skin forward of that area. The so called bug marks are consistent enough in my book with having been in contact with a quite resistant type of bush such as wattle or similar light and reasonably soft branched brush. Hence the wide smudge and usual red colour from such material.
Before I would go jumping up and down about the product I would get the pilot in a corner with some hard questions.