Intellisense not working and removes typed code that matches

The intellisense drop down appears after clicking the dot following a class reference. It does show me the available methods. However, if I arrow down and press enter, or double click one WITH PARAMETERS nothing happens (methods that don't accept parameters work). If I manually type out one of the available options- all the code I typed will disappear as soon as I put in the first parenthesis.

Please see attachments for full IDE logs of the error; one for Click and one for Keypress