FBA but not Prime Eligible?

Just sent some stock in and although it’s showing as fulfilled by Amazon, it’s also saying it’s not eligible for Prime and is showing P&P as a whopping £4.49.

I was only replenishing stock and it was Prime when it was in stock before

Is this something I should be worried about or just another screw-up by Amazon? Has anyone else had this happen to them, and if so what was the outcome?

Cheers