I had heard about the explosion last week but was not aware of the second incident on Mar 1 nor about the cruise lines reaction.
Below is from the Canadian gov site in a travel advisory.
Playa del Carmen
On February 21, 2018, an explosive device detonated on a popular tourist ferry in Playa del Carmen, Quintana Roo. The explosion injured over twenty individuals, including tourists. On March 1, 2018, local authorities found another explosive device on a ferry also operating out of Playa del Carmen. Some cruise lines have cancelled excursions using ferry services in Playa del Carmen. Avoid tourist ferries travelling in the region until further notice, be vigilant and monitor local media (including social media).