Immersion heater power diversion?

Has anyone had any experience using one of these. I have an Optimersion diverter (no longer made) which worked fine until my batteries were installed last week. It would get confused by the battery charging from grid. I've shifted the current meter clamp from the consumer unit to before the power company meter in the outside cabinet. It now seems Ok but it still seems undecided on what to do especially when the load suddenly changes. I think the inverter reacts quicker than the diverter but I have no figures.

I have an Eddi from Myenergi. overall i am very pleased with it, plenty of settings to avoid battery drain and using one of their Harvi ct wirless clamp devices makes install much quicker.
no alexa integration though and the add on board though great for monitoring water temperature has no app control, only timed settings.

Happy to be told I'm wrong but I would have thought that if your batteries are charging from the grid then they are no different to any other load and your diverter would react accordingly and not try to use any power. I would have thought the conflict would be where solar is greater than the load leaving export for the battery and the Optimersion to fight over.
If the 'indecision' over sudden load changes is it only very brief you might not be able to do much unless you can alter the Optimersion surplus recognition. Another thought is could it be an electrical noise problem? If so perhaps twisting each CT clamp cable pait and then keeping them well separated may help.
I use an IBoost to do the job and the surplus recognition can be set, in my case I think 150 W which seems to run IK.

I had a real problem with my solar iboost+. I’ve had to set its “kick in” limit to 350w. That means it only starts the immersion when it detects 350w of excess. Kind of sucks as that’s a big chunk.

Anything lower it was constantly turning on, even at low power, draining my battery. Even when solar was off in the dark.

I too have an iBoost, and although it is quicker to "pick up" on the resumption of solar output after a cloud has passed by, it seems that after a little while, my Ge AC3.0 takes over and takes the power back to charge the batteries. Having observed this a few times now, I am happy to leave the immersion switched on via the iBoost all the time, and not worry about problems that are, really, transient. I have never seen the iBoost actually take power out of the batteries, just temporarily hog solar panel outpu..

Another example of how these things can take a little time to sort themselves out.