Floating Vines

For some reason, this vine spawned connecting to nothing, with no other vines above it. Why is this vine Not connected to the ground nor connected to a vine above it? This makes no sense! If it were connected to the mangrove tree next to it, the back of the vine SHOULD be attached to the wooden log, but it's not, nor is it connected to anything else.

World's seed: 822688500
Coordinates where you can see this glitched vine: X=601, Y=68, Z=692

Edit: After making a creative mode copy of the world, the glitched vines were gone from that spot, but showed up elsewhere, so it might be a minor glitch in world generation or something.