re: #6 Love-Child of Cassandra and Sisyphus
Ah, I missed that thread! Firefox seems to be maintaining its own certificate cache, but it will probably expire there too pretty soon.
Chrome isn’t the problem - Letsencrypt let their old root certificate expire and just installed a new one that relies on a new protocol that older devices don’t support. Apparently the possibility that they were causing chaos for many, many users never entered their heads.