Frames converted to slots don’t show up in downstream instances after publishing

I’m working with a library built before slots existed. Like many older libraries, its components use the old pattern: a frame preloaded with component instances, most of them hidden.

For example, a select menu component holds a stack of select-row instances, most of them hidden.

I converted the frame that holds the rows into a slot so the rows can be edited freely downstream. After I publish, the slot doesn’t appear in downstream files. This happens with existing instances and with freshly inserted ones. The freshly-inserted instance just continues to show the old non-slot build, no matter what I do.

Strangely, if I copy the menu component with the slot directly from the library file, then paste it in a downstream file, I can see and use the slot, but pulling updates from the library file converts it back to the pre-slot construction and wipes my overrides.

• Is this expected behavior when converting an existing frame to a slot?
• Is there a workaround, or do I need to rebuild these components with slots from scratch?

Thanks!