Wasn't it said when Phil rejoined this year that he would have the involvement of his Norwegian goalie coach and that he would also have an input into practice sessions. If it is a disagreement between him and G that is behind this then I would guess the conspiracy is no deeper than a disagreement linked to this and maybe some questions over his performance, which has at times maybe not lived up to his fully deserved reputation. Also, as he seems to have close links to Norway a move back over there is hardly surprising, especially if options were limited at this time of year, it's not exactly a bad place to live.
I also doubt this came out of the blue to anyone however, so I too will be surprised if a good replacement is not in place pretty quickly. As suggested above, Someone already in the UK, or certainly in the EU would make sense and I hope this will be the case, but we shall see.