Special characters all delete text behind them when typed after

Steps to Reproduce:

1. type text, then return, then some more text
2. move cursor to the end of the top text line
3. use a § modifier than type some more text

Observed Results:
After the modifier is active the cursor visually goes down to the beginning of the line underneath,
and everything typed after deletes the text before the modifier

Expected Results:
The cursor would stay in front of the modifier,
and text before would remain unaffected