When Shadow of the Tomb Raider came out, it was accompanied by a day-one patch that offered various fixes. Fans have now discovered that among those changes was the removal of a different possible ending for the game. People have been playing the unpatched versions of the game to see this after-credits segment. Square Enix apparently sent out a note to members of the Tomb Raider Official Fansite Program to explain. (Thanks, Tomb Raider Forums!)
Here is the statement that was shared discussing the Shadow of the Tomb Raider ending that appears before the patch. Siliconera checked in with Square Enix PR to confirm it was official.
During the course of development on Shadow of the Tomb Raider, multiple post-credits scenes were explored. Unfortunately one of the directions that was considered, but not chosen, was mistakenly included in the game. The Day One patch fixes this error, along with many other improvements. As always, we highly recommend that our players install the patch to enjoy the complete and most up-to-date experience.
If people want to see the cut Shadow of the Tomb Raider ending that the patch removes (and do not mind spoilers), Daft Raider has uploaded it to YouTube.
Shadow of the Tomb Raider is available for the PlayStation 4, Xbox One, and PC.