Form Upload image not updated in CMS by zapier

Hey guys! need a quick help. I have set up a membership site and database using memberstack, zapper and Airtable. There is a ‘upload file’ form trigger that is supposed to update the member’s collection (field milestone 1) with the image uploaded.

The problem I am facing is that a for a newly signed up user, this zap update is not working. I see that the Webflow member id(also the slug) is not fetched. However if the same user logs out and logs in again, his uploaded image is updating the required field.

Someone please help me on this. Spent way too much time to fix things up. I have put a html embed above complete button to fetch ‘member_webflow_id’ which is not being fetched by my zap for a newly signed up user I guess.