Hi, this came up whilst driving back from work on sunday (28/6/20).
Has it come up on anyone else's PHEV before?
I think i've worked out how it came up. I'm a keyworker and since lockdown (UK in March), I've been using the battery only -to get to and from work. I can do this without using ICE. Since i've not gone anywhere else for 3 months I've never used ICE. Infact the last time I filled it with petrol was 27/3/20. I assume therefore the petrol in the tank was getting old, the car sensed it and wanted me to mix in new fuel.
Interestingly whilst I was driving home from work on sunday and back in on monday the car opted (automatically) to use petrol to charge the battery (I couldn't override it) - it got me up to 32 potential miles on the read out. On route to work today I filled up the tank which took a maximum of 15.2L and car started running on battery again.
I think i'm going to run the petrol tank low and not recharge the battey until then.