Signature must be zero for failed CHECK(MULTI)SIG operation

[educob]

Hi.

I have a unit test running a generic script that has been working flawlessly. But some days ago I made some changes and got into trouble so I undid the changes.

But now the unit tests fails around 50% of the times. Every time I create new bitcoin addresses, the script, etc.

The script has a multisignature with its public keys sorted as in the test code.

What can cause random failures with error Signature must be zero for failed CHECK(MULTI)SIG operation?

Thanks.