The green node converts 4 gems to your colour at the beginning of your turn, however I have seen multiple times that the gems are converted to other colours than Green (I used Nissa4) sois that a bug or a misreading of the wording?
it seems this issue is back
https://forums.505go.com/discussion/76949/race-to-orazca-green-node-support-changing-gems-to-non-pw-colors-investigating
It also looks at your opponent’s colors. Always has been like that. (still may not be correct though)
It appears to be converting to opponent’s colors. It’s not correct, but this is what it’s doing. If I’m running mono green against Vraska, on my upkeep; a ton of gems convert to black, if it’s Kiora a ton blue, Samut a ton red. But since I’m running mono, on Greg’s upkeep they get a sea of Green and I’m left scrambling for a match 3.
Super huge advantage for the AI here.