Waiting executions > 65 seconds would indeed be persisted to your database, so it sounds indeed like there could be a time zone mismatch somewhere along the way. I was, however, not able to reproduce this based on the data you have shared.
Can you confirm how exactly you have configured both n8n and Postgres? Ideally share a full docker compose setup using which the problem can be reproduced? I tried using the below setup, but Waiting works as expected for me:
PostgreSQL would store the waitTill timestamp in UTC, but that doesn’t stop n8n (using America/Recife time) from picking up the waiting execution as it should.