We need the save because it is a player-specific problem - and most of the time it has nothing to do with the Shards of the Grail objective, it is more due to the Siege of Eboracum quest or that the quest after it does not trigger - but again, it does not affect all people, it's a specific issue that comes up if you did something unintended in your game before. If you want us to check what causes this in your case, please send the save, otherwise we can only assume you have the same issue that we already fixed based on other people's saves - and if it is somehow not, your issue will not be fixed in the next update as we did not know about that specific issue because we did not receive the proper save.
Hope this explains why we need it

Also, many times we ask for a save because it simply makes us easier to find the problem quickly. But in your case we wouldm't be able to reproduce the issue without receiving saves from the community.