Transaction hash collision?

[tcpim]

Why can there be multiple transactions with the same hash? It seems their content is also the same but the timestamp is different. Is that a bug?

Transaction: 10a11eaded2d0f8f1d28641a4115bf43b40591585922df8189831760cbf559c9

These two transactions have the same hash but different index. Can somebody explain how does the index work with hash? Thanks!

Transaction: 10a11eaded2d0f8f1d28641a4115bf43b40591585922df8189831760cbf559c9

Transaction: 10a11eaded2d0f8f1d28641a4115bf43b40591585922df8189831760cbf559c9

[ZenVoich]

Is the transaction hash unique in ICP?

Uniqueness of transaction hash is guaranteed for the transactions that have the created_at field set. For these transactions the ledger ensures dedication. If created_at is not set then there may be duplicates