After some further investigation, this behavior occurs when adding a space to the end of a non-empty line as well. Tabs do not seem to produce this behavior. If a space or newline is added before some visible character on the line, the character is inserted properly and no freeze occurs.
After some further investigation, this behavior occurs when adding a space to the end of a non-empty line as well. Tabs do not seem to produce this behavior. If a space or newline is added before some visible character on the line, the character is inserted properly and no freeze occurs.