I think it was the Edit-Substitutions-Text Replacement being checked that caused the problem but I am not sure. If I tick it now I get a similar problem to the one I had in the first place. Either way it was Step 3 that fixed it.
If Safari still doesn’t work right, quit, go back to the Finder and move the following items from the open Library folder to the Desktop (some may not exist):
(Note: you are not moving the Safari application. You’re moving a folder named “Safari.”)
Try again. This time Safari should perform normally, but your settings and bookmarks will be lost."
Linc, I'm having this same issune on my iMac & MBP. I'm using iCloud and when I performed your steps 1-3 it seemed to be fixed for a couple hours, then back to the original issue. I'm the sole user on both machines.
Is there something with iCloud I need to disable and try again?