I think, and hope, this might be the influence of Jeff Sessions. That Sessions staff member went to work for Trump just a few days ago and he also issued a very good statement for the Trump campaign, yesterday, I think.
I believe Sessions might be moving more towards Trump after his warnings this week about TPP which was just signed in New Zealand with no publicity. Trump has been strong against TPP and Cruz entirely unreliable after his vote for TPA.
Could also be from Scott Brown, the former Mass. US Senator, who's endorsed Trump.
Scott gave a long interview on WBZ last night and said he'd spent a lot of time with Trump in the last few days.
And of course Trump could've figured it out on his own.