Gotta say, bugs me too that Hope is never called Gramma in person......but since Days does this "one take" rule, and no rehearsal, maybe Marlena just slipped up, calling him John......
Heck, when you watch a blooper, you see these serious faces saying lines, flubbing, and bursting out laughing. Nowadays, they have to plug on! LOL
The other day, Chad was talking to Sonny, and made some remark to the effect he would not recognize straight, it was something about "straight". Sonny smiled....and later Billy Flynn (Chad) tweeted that the line was an adlib on his part. See. Sonny knew that, grinned, but continued on. In the old days, he would have burst out laughing, Cut, redo the scene. LOL