To think a post from 2014 ended up helping me big time! I decided to reinstall original Skyrim after a while to enjoy the extra mods that it has over Skyrim SE, to suddenly find these weird and TRULY messed up shadows. I had the exact same issue as you! Some strange shadows following your character everywhere you go, followed by disconnected shadows everywhere. It was unplayable lol. The weirdest part is, I never had this issue many years ago, strange that a fresh Skyrim install brings this issue. Neverthless, thanks a TON Rvrstyxx, you were my savior tonight. I searched many threads and none of them had this exact problem. Best of all