Just following up here with some more info - this is indeed an issue in WordPress and a Trac ticket is open for it - #59111 (A stale register_core_block_style_handles cache can cause styles not to load) – WordPress Trac
In the meantime, an even easier fix is noted in that ticket - Opening a Site Shell in Local for the sites affected and running this command will resolve the issue:
wp transient delete wp_core_block_css_files
We’ll stay on top of that Trac ticket and keep pushing it along where we can.