Flexbox child button not stretching or aligning left/right

Hey all,

I have a vertical flexbox div with two stacked buttons inside set to align:stretch. The first button behaves, but the second button ignores this as well as its own flex child align settings. It has no defined width, no margins, and im at a loss. any help would be awesome! (see screenshot). Here is also my read only link:

Here is my site Read-Only: LINK
(how to share your site Read-Only link)

I’m dealing with the same problem, so I’m really hoping you’ll get an answer on this!