I have the same problem - it is something to do with Eonnext loading their software or config. onto the smart meter. They don't respond to the problem hoping it will go away. It is not the display unit.
This is actually not the case. I'm not the kind of person to defend E.On (I'm actually supplied by OVO) but I will not hesitate to intervene in order to dispel misinformation or speculation.
I've been seeing a lot of reports recently about the Chameleon IHD3 having trouble with getting data from meters. My friend Blastoise186 has also seen even more reports elsewhere. It's definitely not an issue specific to just one supplier, nor is it related to any config or software deployed as such. True, suppliers can run their own code to an extent... But there's limits to that capability for security reasons. Naturally, supplier specific configs are also a thing, but these are mostly related to things like encryption keys, tariff configs and a few other bits and pieces. Nothing particularly interesting or fancy, so to speak.
The best I can suggest right now would be to flag this up with customer service, so that it can be investigated. I wish I had more advice, but as me and Blastoise are just forum volunteers and don't work for any energy suppliers, we're both limited to publicly available resources.
SmartMe for example, being one of the really good ones if you'd like to know how it all actually works.