Hi Jeremy,
Ironically, it looks like the issue has resolved itself, but here is all of the info in the event it happens again or someone else is having the same issue.
I opened up my wiki in Microsoft Edge and had no issue editing tiddlers. I'm wondering if perhaps doing this fixed whatever was going on in Chrome, because as of today, my wiki is working fine in Chrome. I did install CodeMirror, but that did not initially fix the problem. I do use several Chrome Extensions, including Evernote, Lastpass, AdBlock, TimeWarp, Momentum, and Pinterest. A few running in the background are Logitech Smooth Scrolling, Adobe Acrobat, Google Docs Offline, and the application launcher for Google Drive. Not sure what fixed the issue, but everything seems to be working. If that changes, I'll post an update.
Jett