Check
tag. Usually the page has several candidates (an H1 that disagrees, an og:title from a template, or a title reused across pages) and Google picks for you.
Google shows the wrong title or description
Search results use a different title than your
How to confirm it
Run this against your own domain:
curl -sS https://example.com/page | grep -o "<title>[^<]*</title>\|name=\"description\" content=\"[^\"]*\"" | head -4
How to fix it
Make the title unique per page, front-load the subject, keep it under about 60 characters, and keep H1/og:title/JSON-LD headline consistent with it. A description that repeats the site tagline on every page gives Google nothing to use.
Where it fits
This is a symptom of a failed check — here it points at B1. The failure it belongs to is only one of fifteen; the full list is in the standard, and the fix order that avoids redoing work is in the repair guide.