My Maples are always in full sun. I do not get leaf burn. As long as the roots do not dry they are fine. Peter Chan has all his Maples in full sun, also.
Leaf burn is more likely with windy conditions, and dry roots.
The only time I shade any trees is when it is too hot and I can't keep them watered enough.
Last year was the first time I used shading for about 5 years.

Hmm, thats wierd, yes in summer when the tree is in full steam being in sun is not a problem and if it leaves do burn only in hot days and just the outher contour gets twisty and brownish slightly.. Now the tree is always watered and because its an inported young nursery material its still in dark soil so im watering it kinda rarely by this time because of cooled of weather the last week and the tree didint need watering for maby the 4th day going... The buds are swelling alot but not full steam yet and all of them and their healthyness dont drop my eye on poor watering.. And it got its young stems or old last year shoots burned by the top till whitenes but even that the tree started to kick buds at the end of those stems/shoots where its still more red so i dont know whats the case.. And maby if the tree is pushing buds in the less burned part of the stem maby i should prune off all the burn part??

Sorry, I should have said that they are very vulnerable in spring until they are fully open. I do protect from frost early in spring, they are almost open now, and so are fine. We have not had much frost so they have been ok. The one that is very tender is Kiyohime Maple, I have kept mine under cover until it is fully open.
I would leave the damaged leaves on, but it is up to you if you prefer to remove them