If I'm reading it correctly, the document only shows one password challenge, but the two-screen presentation is the first screen (shot 2) for username to send you to the appropriate auth system, and the second (shot 3) to input your credentials.
Is the last screen repeated? otherwise i'm not sure of the problem
Regardless, this could be an issue in how the federation (etc) is set up.
It's probably best to reach out to us in a support context to continue, as we may need to discuss more specific details privately.
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Ted Phillips
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