1080i 50 issue

I have a few blu-rays encoded at 1080i 50hz, how come when the frame rate is set to auto, instead of playing these files at 1080i it drops the resolution to 720i instead and plays it at standard def?

Its really annoying, I want to watch in HD.

720i?  Not sure what you mean because there’s no such thing as 720i.

Interlaced video is only supported at 480i (NTSC) / 576i (PAL)  and 1080i.

Sorry, I meant 720 x 576 interlaced. It’s a PAL 1080i source but it plays it at 576i.
Any reason for this?

Hopefully someone with similar media will chime in; I have no PAL sources or PAL TV to test against.

Hopefully, because this is really annoying. Why does it keep playing all my PAL stuff in standard definition? That’s ridiculous.