According to this, he was once asked in an spanish interview about it and his answer was
does Robotech exist? What is that? Does Macross II exist?
I found more about this recently. Very interesting actually
“When it comes to Robotech, it's difficult to comment. It's not as
though I have sat through the whole series. Not to mention that it
combines three separate series Macross, Southern Cross and Mospeada.
So it feels a bit forced as a result.”
“At the same time, this was an opportunity for our work to be shown to
the world and for that I am thankful. However, because the partial
change in the story was made without approval from us, the original
authors, it still produces an uncomfortable feeling after all these
"As for the recently announced live action Robotech movie, I welcome
the opportunity to work on it but that request has yet to come."