I would test for a while with them all unplugged. If that solves the issue:
The Zen15 can be heavily adjusted to reduce the reporting. Try this driver [DRIVER] Zooz Smart Plugs Advanced (ZEN04 / ZEN05 / ZEN14 / ZEN15)
The defaults I set on that driver should not be too bad but you can fine tune it more. Turn on both logging options and you will be able to see every report that comes in (for 30 mins on debugging). Disable or increase thresholds for any power reporting you do not use.
I will check out that dome plug later.
