When calling execTransaction manually, it fails with GS026 - Invalid owner provided

Question

I have signed the gnosis transaction with 2 owners and I can see this correctly in the Gnosis UI (i can even execute the transaction there). When I use the API, I get 2 confirmations with signature fields.

When trying to call the execTransaction method in the Gnosis Contract (using the first signer or another owner), I am concatenating the signature fields from confirmation, however, I get GS026 - Invalid owner provided.

I checked the gnosis contract and the failing line is

require(currentOwner > lastOwner && owners[currentOwner] != address(0) && currentOwner != SENTINEL_OWNERS, "GS026");

However, I don't know exactly what is wrong because I used the third owner to execute the transaction (it requires 2 confirmations).

Can someone give me some hints? Thanks

EDIT:

Signature generated by Gnosis UI:

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

Signature generated by my script:

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

Also pasting a screenshot from a diff tool: