Recently, someone always says "I've checked on the chain," but frankly, what you're seeing is just what someone has presented to you on the chain. Slow node synchronization, RPC hiccups, indexer queue blockages—your "real-time" might already be half an hour late... I've personally experienced transactions clearly confirmed in a block, but the tool still shows unconfirmed, almost trembling and doing the operation again.

These days, I've seen people question the lag in on-chain data tools/tag systems, or even that they can be misled, and I'm actually not too surprised: tags are basically like sticky notes someone else sticks on you, and if they stick it wrong, you can easily believe it. My current approach is to patch small fixes: keep a record of key addresses yourself, compare with two more RPC/browser tools, it's more trouble but don’t just rely on one panel. Anyway, my obsessive-compulsive disorder makes me treat it as a way to extend my sense of security.