The problem nobody notices
Over a few years a business accumulates listings: a directory entry from 2019, an old Facebook page, a supplier profile, a map pin someone else created. Each one holds a snapshot of your details at the moment it was made.
Then you change your phone number, or move premises, or start trading as something shorter. The old entries do not update themselves. Now there are four versions of you in public, and search engines have to guess which is current.
What consistency actually means
Pick one canonical form of your business name, address and phone number — the "NAP" — and use it character for character everywhere. "Ltd" or "Limited", "Street" or "St", with or without the unit number: pick one and never vary it.
This is not superstition about exact-match text. It is that a machine comparing two records with different phone numbers cannot tell whether they are the same business or two businesses, and the safest thing it can do is trust neither very much.
Where to fix it, in order
Your own website first — it is the record everything else is checked against. Then your Google Business Profile, then Bing Places, then the directories that actually send you visitors, then the long tail of old profiles.
Delete what you cannot correct. A dead listing with a disconnected number costs you a customer who assumed you had closed.