Odd behaviour with Safari in iOS 13

I’ve been using HA with a bunch of Sonoffs reflashed with TASMOTA for a year or so. Once over the configuration hurdles, everything settled down nicely. Until today. So, I updated my iPhone 7 from iOS 11 to iOS 13. Now, when i go to switch lights on, I have to try 3 or 4 times. They go on-off when I click the browser, then after a few tries, they go “on-off-on”. the converse is true when switch off: they go off-on, etc.

Pretty sure this is not a problem with HA, nor my broker, since Chrome in Windows 10 still works fine, as does the default browser on my Android phone. Further, pretty sure my broker is OKay as the MQTT Dash app (Android) continues to work perfectly well.

Has anyone else seen this or have any suggestions?