Consent wall
A consent wall is a banner or overlay that blocks interaction with a page until the visitor accepts or rejects something, most often cookies, and which therefore sits in front of everything else the page contains.
Presenting the choice is an obligation in many jurisdictions. Making it impossible to express is a configuration decision, and it is the part that stops an agent: a control that is a styled element with a click handler cannot be operated by anything without a pointer.
Because an agent carries no cookies, the wall fires on every visit rather than once, so a store that is otherwise perfectly readable can fail at its first page every single time.
Why it matters to a store
The fix is the same change that makes the banner usable with a keyboard and a screen reader, so there is no version of this where accessibility and agent readiness disagree.