As noted earlier, via John Pollock on Twitter, travel issues involving WWE personnel and talents for tonight's RAW in Montreal were forcing things to be re-written for tonight's Superstar Shakeup episode.
In an update, a combination of bad weather and flight cancellations in Newark, New Jersey was impacting who was be able to get to tonight's RAW on time, according to F4Wonline. There were several WWE Superstars who were booked for layover flights in Newark, and it was noted that it's just a bad travel day, and the few people who did have minor border issues were known in advance.
On a related note, WWE United States Champion Samoa Joe is reportedly at RAW, but is said to be very sick. He was booked for a segment on tonight's show, but that segment was reportedly being removed from the show. There's no word yet on if they had plans to move Joe to RAW from SmackDown.