No, absolutely positioning does not conflict with flex containers. Making an element be a flex container only affects its inner layout model, that is, the way in which its contents are laid out. Positioning affects the element itself, and can alter its outer role for flow layout.
That means that
-
If you add absolute positioning to an element with
display: inline-flex, it will become block-level (likedisplay: flex), but will still generate a flex formatting context. -
If you add absolute positioning to an element with
display: flex, it will be sized using the shrink-to-fit algorithm (typical of inline-level containers) instead of the fill-available one.
That said, absolutely positioning conflicts with flex children.
As it is out-of-flow, an absolutely-positioned child of a flex
container does not participate in flex layout.