The other question was not about how to verify the integrity, but rather about how to fix a particular warning message. The answers explain how to remove the warning message.
Later I found the answer to my own question. It turns out the warning is triggered by a check which is sort of redundant, because the real integrity check is done by a hash tree totally unrelated to the signature generating the warning.
This means taking any of the answers to that old question and apply to my question, it would in fact be an incorrect answer.
On the other hand, the answer I found to my own question tells me, that the warning can be safely ignored, because it is not part of the integrity check. This would not be a good answer to the old question about how to fix the warning. If you ask how to fix a warning, the answer you are looking for is not to just ignore it.
Given that a correct answer to one question would be an incorrect answer to the other question and vice-versa, can they still be considered duplicates?