@StndCpp (and his Wife) have rightly pointed out two key insights:

1) Each of the messages in the red and green channels end in the letter 'z'. This is very likely a string terminator character.

2) There are 2 extra columns of text in the green channel I missed:

So there is a full message in the green channel after all:

Green Message:

a haiku
a person amazed
reading this text just right now
this is the wrong place

It looks like the text ends there since the 5th column ends in "AMYCB" which doesn't have any apparent meaning.

Update: I accidentally pasted the haiku lines out of order in the original post. Should be correct now. Thanks @Jacob Waite!