Tvheadend

I've been running Tvheadend for years, currently using versions HTS Tvheadend 4.2.8-36~g5bdcfd8ac and HTS Tvheadend 4.3-1986~g09a2c71ab. Sometime since the start of the year (I think) Tvheadend has started displaying the times in UTC rather than local time. My SUSPICION is that one of the upgrades to Ubuntu Server might have changed something. It is particularly noticeable if you go to the Digital Video Recorder / Upcoming/Current Recordings tab - both the time display at the top of the page and all the scheduled stop and end times are now in UTC. The programs still record at the correct time, they just display in UTC. And it's not because the XML file that contains the listings uses UTC; those listings are in local time followed by a space character and a UTC offset, but they have always been in that format.

I just wondered if this happened to anyone else, and if so do you know how to get Tvheadend to display local times again? Or why this happened in the first place?