No Import Layout button

Hi,

When creating a new Post/Page, we are supposed to see the big “Import Layout” blue button, but I don’t see it anywhere, there’s simply nothing.

But, I use a Row block, then it appears below the “Select Column Layout” options, as it should be.

My site is a brand new one for testing purposes, running the Astra Theme. Everything is updated to the last version.

My plugin’s list is:
Classic Editor
Gutenberg Editor
JetPack
Qubely
WooCommerce
Block Pattern Builder
Reusable Blocks Extended
WordPress Importer
Query Monitor

Deactivating the other plugins seems to have no effect.

So the only way of importing any layouts is having a row block first.

Thanks in advance.