COYS68 there's a couple of potential issues at play, which unfortunately you have very little control over. These manifest themselves when you have fragmented Octopus charging schedules.
1) if you're on a newish firmware, the Zappi has a built in "up to 10 mins" delay, for grid balancing. This shouldn't be there for IOG, and MyEnergi know it's a problem but seems reluctant to fix it.
This only really affects the first slot in a schedule, but can mean (if the first slot is set to start at say 20:56, the charger misses is and rolls into the next half hour, which may not be in the schedule, so your car is charging in a non-scheduled slot.
2) IOG slots have become far more dynamic recently. It's not unknown for Octopus to change a slot only a few mins before it was going to start. If WW has already sent the instructions to your inverter, it then leaves your batteries charging when there's no longer an IOG slot.
Octopus want us to plug in more frequently and ask for smaller amounts, but this is only going to exacerbate the situation IMHO.
This sometimes causes me problems too.
Going forward, I think one way of dealing with it will be to ask for plenty of charge in the shortest time, and use the "limit to 6hrs" button Octopus say they will add to the app.
It's not how they want you to use it but, unintended consequences and all that.😟
