I updated all our development sites to WordPress 6.4.1 (from 6.3.2). They were already using Toolset Blocks version 1.6.8 so nothing about Toolset changed. After the update, most of the Toolset blocks have disappeared from the interface (some sites show only content template as an available block, others show none). In the block editor, anywhere I have a Toolset block I see a message something like "Your site doesn’t include support for the "toolset-blocks/button" block. You can leave this block intact, convert its content to a Custom HTML block, or remove it entirely." I can't edit/save any pages without losing the content. This is happening across a range of sites using different plugins so it is hard to provide exact debug details. Note that they all use the Astra theme and that was updated at the same time so that seems to be one of the other consistent factors.
Sorry, the sites all said Toolset was up to date and running updates with WP-CLI did not catch it. I found these versions on the website and did the update manually and things are ok now.