Doing some quick searching, it seems that we currently do not know how the plane crashed. It was in the air on a mission to shoot down cruise missiles, and after doing that on the way to another target they lost connection. It will likely be a while before we know, both because it will take time to investigate but also depending on what the cause was they may not want to release it publicly for a while.
Slightly more informative article I found: https://www.nytimes.com/2024/08/31/world/europe/ukraine-f16-pilot-crash.html
A bit more context from reading the article
the bear was actively going through the trash of a woman’s summer house while she was there which is why it was reported
the Iceland environmental agency actively decided to not try and relocate it, likely due to how expensive it would be to take back to Greenland
the bear is also being studied for potential diseases/parasites, how healthy it was, body fat, etc. which is nice I guess