Doesn't bother me in the slightest. The GC at the time knew he wasn't actually signed until the cooling period finished. Didn't they offload Hayne last year because he wasn't any value? Don't the Roosters sack players the second someone better comes along? Didn't we tell Wallace not to sign elsewhere because we'd re-sign him, then didn't and screwed him over financially?
It's very, very low on the radar for me of scummy things to do. He did everything within the rights that the stupid rules at the time allowed him to do to maximise his financial earnings. He entered the NRL scene fairly late (21 I think?) and his career, at any point, could be cut short as we've seen with Yowie, McKinnon, and a number of other players.
Him not taking an 8 year deal would have been stupid. GC offered him 4 years, Manly countered with 8 years, with better money. Any reasonable person would take that.