🇺🇸United States @MarkGeater

We encountered the same issue. It's because Drupal 10.2.6 introduces a new asset validator, and one of the checks is that library names contain exactly one forward slash. This is the reason for the bug reported in this thread in the Asset Injector module.

In our case, we had a library name in the site theme that didn't contain any slashes. I recommend checking all of your custom module and theme libraries.yml files to see if you have any library names that don't match the expected format.

We had this issue and can confirm that the patch in #3 works as expected.