It seems like it's SOLVED. It had an area in the area which somehow masked off the outer part's visualization. So basically someone in the past added a forest area inside a bigger forest, and that area was somehow open(?), which caused the map to render it as an empty area, when the inner area got disturbed.

It still seems to me that the area is preserved and shows that it IS a forest, but the Standard Imagery renders it as Totally white, like the area is not a forest. Maybe there is a problem with the standard imagery rendering?

Problems. BIG PROBLEMS. I screwed it up. Can I somehow reverse this? The markers clearly showed that the area I deleted was surrounded by a forest, so if I deleted it, the forest would take up it's place too. To me it still shows it, BUT the standard imagery started to remove those parts, so I assume something went wrong.

Thank you all for your comments and advices. I will be more careful next time.