Add a subcollection to collection not working

[KatharineV]

Prior to the cutover, I believe we could keyword search for collection names in order to add works to collections and/or add existing collections as subcollections to parent collections. Testing today, I see that there is no keyword box and the dropdown only gives me access to a handful of the hundreds of collections that exist. We need the keyword box to be functional for all "add to collection" actions in all places (but I'm creating this ticket for just the one scenario I've tested and seen doesn't work). The keyword box also needs to accept single word searches, which production did prior to recent changes. We have several single word collection names, and so this functionality is critical.

Collection I tested. I need to add "Spectrum" to this parent collection as a subcollection.
https://adl.b2.adventistdigitallibrary.org/dashboard/collections/8566e1eb-043d-47a8-89cd-24b604365532?locale=en

No keyword box:

And limited selection list in the dropdown: