What
One reason sync can report, "stale_basis", has been removed. The message for "deferred" now says the item is left for the next sync there, which tries it again.
Why
A deferred item is retried on the next sync, so you do not need to act on it.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
The finding does not say which sync feature these messages belong to.