Regression - Issue wont happen In earlier versions.
When typing a source name within the source clone properties it will prevent typing if it has found anything that matches.
(Example)
OBS Sources: Abc, Alpha, Bravo, Charlie, Source Clone
Source Clone Properties:
Select Clone Textbox: Press A (Prevents further typing autofills Clone to Abc)
(Reselect Clone Textbox)
Clone: Delete "bc" Press "L" (Prevents further typing autofills Clone to Alpha)
If no matches then can continue typing.