Homekit automations not working

First, my iMac and iPhone are both running the current OS. Starting about 2 weeks ago, my Homekit Automations, which configure smart plugs to turn on and off as certain times of the day, will not stay set. It will always change back to another, apparently arbitrary, time scheduling. This occurs whether I use the iMac or iPhone Homekit app to try and setup the Automations I want. What should I do? Delete the Homekit app and start over?