Found the boat!
After some investigation I think I have identified the boat the mysterious judbas@?????.pl was on.
Specifically the Ortelius - which took a number of tourists on a month long trip around the area in March/April 2015
The Ortelius was located off-shore of Bouvet on April 6 and 7 of 2015 but was unable to land. My suspicion is one of the tourists set the bottle afloat at that time.
Here is a travel blog written by a Russian that details them being off-shore at Bouvet at that time: https://www.tema.ru/eng/travel/bouvet/
I emailed the blog's author to see if he can identify the mysterious judbas@..pl