The call to FMemory::Memset() in UTexture2DFactoryNew::FactoryCreateNew() appears to reverse the expected order of the second and third arguments. Most other calls to FMemory::Memset() appear to send the arguments in the order Pointer, Value, Size (I did not look at every call to this function in the Engine), but in UTexture2DFactoryNew::FactoryCreateNew() the arguments are sent in the order Pointer, Size, Value.
RESULT:
The function call includes the arguments in the following order: Pointer, Size, Value
EXPECTED:
The function call includes the arguments in the following order: Pointer, Value, Size
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-56399 in the post.