uploaded bug.png. Replicated in 25w02a
It is quite important to note that contrary to what this report claims, the game modification suggested by this report as a potential solution does not preserve vanilla behavior that has existed for a very long time.
Should be clear from the writeup, but this affects versions since 23w45a, and 1.20.3 is the first full version that it affects. But the "Affects Version/s" box wouldn't accept anything but 1.20.6.
Just tested both world download examples in 1.21.5, following the provided instructions. The pearl did not teleport me in either example, even after multiple minutes of waiting for it to do so. Also, there were command blocks set up to record in chat the location of the pearl, and the chat output stopped soon after the pearl began traveling, indicating that the entity selector was unable to find the pearl at all due to it being unloaded.