RDM prompting twice for credential

For most of my RDM entries, I have Credentials set to "find by name (user vault)" with an empty box next to it. This generally does what I want and pops up a credential selection window when connecting. However, on most, but not all, entries, it pops up the credential selection box twice. I just have to select the same credential twice and everything else works fine. I haven't been able to narrow down what the difference is between the entries that ask once and the entries that ask twice. Is there a way to make them all ask only once?

For context, I'm using DVLS and Gateway with all of these.