Guests with sailings booked on Royal Caribbean's Allure of the Seas are receiving emails from the cruise line that their itinerary has changed due to a speed restriction.

Emails similar to this one that Royal Caribbean Blog reader scottvfl shared, were sent to guests informing them of the itinerary change.

Royal Caribbean has not indicated the nature of the issue exactly. Based on emails sent to guests, it appears the changes mostly affect Eastern Caribbean itineraries, with St. Thomas often being replaced with San Juan, Puerto Rico.

Propulsion problems are not uncommon among cruise ships, resulting in slower speeds until the issue can be addressed in port. Anthem of the Seas had a similar issue in March 2017, Liberty of the Seas in 2015, Freedom of the Seas in 2014, and even Allure of the Seas back in 2013.

There is no indication yet as to how soon the issue will be resolved.