Cursor jumps to beginning of text

I'm seeing an issue where the cursor will quickly jump to the beginning of the text block once the maximum length has been met.

To reproduce - enable maxlength on a CKEditor field with Force Truncate and Safe Truncate enabled.
On the content form, type quickly at the end of the text string, once the count is at the maximum.
The cursor will periodically jump back and forth from the end of the text to the beginning, inserting what is being typed at the beginning of the text.