The text flickering/flashing issue that occurs when typing with the outline plugin active appears to be back (as of beta 42). It was fixed in earlier beta versions, but now it seems to have regressed. Not sure exactly when it resurfaced. For details on the issue see here and here.
The Outline plug-in has not been changed for a long time, so I don’t believe it is caused by the Outline plug-in. I don’t know what is the problem… I cannot reproduce flicking issue. Can you describe more in details? Please also make sure you have beta 42 installed from the About dialog box.