Short answer
Upwork sometimes creates a job hours before it publishes it (roughly 7% of jobs). Lancer sees a job once Upwork publishes it, and picks it up within a couple of minutes. When the gap between creation and publishing is 30 minutes or more, Lancer shows both times so the age matches what you see on Upwork, e.g. "Published 4m ago · created on Upwork 3h ago". It does not mean Lancer found the job late.
Where you will see it
Lead cards in the campaign feed and the lead side panel: "Published … · created on Upwork …". Hover the time on a feed card to see both exact dates.
Lead queue and dashboard Recent Leads: the usual "Posted" time, with a small "created on Upwork …" line underneath.
Send Proposal: the job card shows the same two-time line.
Slack and Discord notifications: the title reads "Job: …" instead of "New Job: …", with a line showing both times.
Normal jobs
For most jobs (created and published close together) nothing changes: you still see "Posted … ago" and "New Job: …".
Good to know
Older leads that predate this change use the same creation time Lancer already stored, so they show it too.
If a job looks late, compare the "Published" time, which is when it became visible to freelancers on Upwork.