What is up with OneNote 365 - it seems to need to "download" every page to be able to search?

Just moved from Office 2019 Pro Plus to Office 365 - and have noticed something odd with OneNote.

While I am able to connect to my "cloud" notebooks with no issues - and "sync" appears to have "synced" - everytime I go to search something that I KNOW is on a page in a notebook someone in here - the search comes back blank.

Then I go to OneNote on my phone - enter the same search criteria and there it is!

I can easily see the location of the search item on my phone and then go to the same location in that Notebook and click on the same page - OneNote always shows me a quick flash of "....LOADING" and then the content comes down from the cloud (presumably for good?)

What am I missing. Please tell me I do not have to click on umpteen thousands of pages to get a complete search vector?

Appreciate any updates.

S