Dura Ace front shifter issue

I have the new DA group set on my Supersix and the front shifter keeps sticking. To summarise when I shift up there is a small section of the lever which comes out as per the attached photo. It stays out meaning I have to push it back in with my thumb. If I don’t do this it means I can’t change down to the small ring. I tried lube on the shifter but no joy. Any ideas?

https://i.imgur.com/9vXltOq.jpg