Seedfork said: However, that still leaves the issue of the two budding scapes on the fan on the right.
I know because of the rust issue here, leaves have been pulled and broken off, so I suppose there is no way of explaining the growth pattern of these plants further.
I expect that your supposition is correct; there does not appear to be any way to investigate this particular occurrence any further.
You can investigate daylily cultivar growth patterns whether the cultivar in question reblooms or does not rebloom in your location and growing conditions.
Daylilies can be continuous growers or discontinuous growers. Rebloom typically requires a continuous growth pattern, that is, it is easier to get rebloom with continuous growth than with discontinuous growth. Rebloom is possible with discontinuous growth, that depends on how long the growing season is and how long the growth rest period is.