• VSCode Version: 1.25.1
• OS Version: Mac OS X 10.13.6 (17G65)

Steps to Reproduce:

1. Open new file
2. Set language mode to Python
3. type "marry had a little lamb" (w/o quote)
4. insert cursor anywhere in the string and type " (quote character)

Expected results:

• A quote character will be added

Actual result:

• Two quote characters are added

Does this issue occur when all extensions are disabled?: Yes

This bug happens with any line that ends in a character that starts an open autoClosingPair. It's especially prevalent in the Python language mode because Python has so many open autoClosingPairs that begin with a letter, but the bug will present itself in any language mode that has open autoClosingPairs similar to Python's.