Multisite and Tailor Structure Entries

I’ve set my October install (v3.6.26) up to use multisite and am using 2 x sites “English US” (default) and “English UK”.
I’m using a Tailor blueprint to create hierarchical categories as follows:

handle: Inventory\Category
type: structure
name: Category
drafts: false
multisite: sync
...

If I create a top level category in either site, it appears in both UK and US sites. All good!

But, if I then create a category (in either site) and choose a parent category (or use the drag and drop ordering afterwards), it shows fine in the site I’m currently on but doesn’t appear at all in the other site. A duplicate DB record has been created for it but the category doesn’t show at all.

It seems like a bug, or at the very least inconsistent, but I accept I could of course be doing something wrong or misunderstanding how the sync works perhaps?

Hope you can help. Many thanks.

This has been fixed in v3.7.4 - if the multisite mode is ‘sync’, then structures will be propagated by default