https://www.youtube.com/watch?v=5CM_rz3nKLI&feature=youtu.be
A bit of an odd bug, that's for sure, but it allows you to pass through ceilings and/or overhangs effortlessly! All you have to do is be flying upwards, and spam shift.
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migrated
I find it more of a feature. Handy if you don't want to break anything while going to the surface.