Predbat forcing KH7 inverter into Backup mode

[itm60]

I've just started using Predbat with my KH7 inverter. At 11:10 this morning I noticed that predbat was in FrzChrg mode and drawing large amounts of power from the grid. As the solar forecast was great for the day I couldn't understand why it would need to draw any power from the grid to recharge it - according to the plan there would have been enough excess solar generated to fully recharge the battery by 13:00.

I guessed that it was taking a view that exporting would be a good idea as export rates were relatively high compared to the rest of the day (I am on Agile Octopus Outgoing).
At 11:10 I checked again, and even though the battery was at 77%, and solar being generated at >4kW, the inverter was still pulling 1.8kW from the grid to charge the battery.

I then opened the Fox Cloud app and noticed that it was in Back Up mode. I have no idea why - this was not something that I had set. So I changed the mode back to Self-Use, but it immediately reset back to Backup mode.
It was only when I put predbat into read-only mode that the inverter would stop automatically going into Backup mode and drawing power from the grid.
Any idea why predbat is forcing the inverter into Backup mode and force charging from the grid when there is more than enough solar being generated to recharge the battery by 13:00?