in the new release, org-agenda-current-time-string is partly fontified if it contains emphasis like "=== test ===". my guess is best to not fontify as it is not possible to fix unless you turn it off for the entire buffer.
-- The Kafka Pandemic: <http://thekafkapandemic.blogspot.com> The disease DOES progress. MANY people have died from it. And ANYBODY can get it at any time. "You’ve really gotta quit this and get moving, because this is murder by neglect." --- <http://www.meaction.net/2017/02/03/pwme-people-with-me-are-being-murdered-by-neglect>.
