I have been constantly hit with this crash:
Assertion failed: InTexture->IsAsyncCacheComplete() [File:D:/UnrealEngine/Engine/Source/Runtime/Landscape/Private/LandscapeEditInterface.cpp] [Line: 5666]
That happened pretty much every single time I sculpted my landscape, which made the feature completely unusable for me. So I compiled the editor from source and commented out that line. The crashes are gone and I can work with my landscape again, as usual.
Now I am wondering: what does that check actually does, and is it safe to keep it commented out? That looks like a safety check. Could it corrupt my landscape in the future?