Hopefully this is a sign of good things to come and we'll see a release date for the Nightbird collection announced later this year.
I got an email reply from Titan apologising for skipping River of Death after COLONEL SUN had already been released. I don't really think Girl Machine got clearance last week, particularly considering it's coming only four months after Polestar. TMWTGG, OP, OHMSS, GF, CR, DN and TSWLM came out every three months. CS and TGG four months apart, TS, TPP, DW five months apart, SB six. Now, TPP is coming after 5 and PS and TGM after four. I guess, they widened the gaps to have enough time to secure each consecutive one.