The email was sent directly from Regent to us. I did find the below on Regent's website which makes me think it is, as pingpong1 said, fairly standard and it is just about 30 days prior to sailing.
Subject to local requirements, all guests are welcome with no tests required, regardless of vaccination status.
Specific requirements, if applicable, will be sent to all guests approximately 30 days prior to sailing. For sailings outside of 30 days, as the entry requirements by country continue to evolve, we encourage all guests to consult with local government websites to determine any additional requirements that may be required to travel.
As far as the Splendor cruise that recently disembarked in Tarragona: I had been watching that for at least 2, probably 3 months and it was always listed as Tarragona on the website.