4 years ago there was a confirmed issue with the home energy meter and the IQ Panel 2, or more specifically with the Z-wave software, where the HEM would interfere and essentially accidentally jam the network.
Qolsys released a Z-wave update for the IQ Panel 2+ to try to work around it. That exact same version issue wouldn’t apply here, but a similar problem may be occurring.
If you leave the energy meter disconnected for a couple days does the network remain stable?