Sometimes when I load up a and it previews the first boss, it’s not actually the first boss, once the game loads up it is an entirely different boss.
One that just happened was it showed that it would be Marei Loom for the first boss but the actual first boss was Alchemist Wendy
Is it only the first boss? There is a known issue which can affect the whole run:
It’s not just a display bug. Last night after this kept happening and I kept playing, it started displaying wrong bosses all over rather than a Chapter 1 starting boss over and over. I kept playing, and soon it started saying Bob over and over. I kept playing, and then it starting giving me games completely out of order. I would START a run with Bob and FIGHT him, in a completely wacky wrong mechanic. It would skip treasures and put them out of order, it kept saying Bob fight over and over. My runs became garbled messes. I have screenshots of it, but it won’t let me link them. This is far worse than a display bug.
You are likely experiencing a separate but superficially similar issue, or possibly a separate issue compounded by the one described here. There have been other bugs reported with the structure of Dalaran Heist runs. Most people seem to only be experiencing it as a display issue, though. You can post your screenshots by wrapping the links in reverse single quotes.
You can paste the link here, surrounding it by backwards single quotes (or using the “preformatted text” button </>), `like this`.
Here’s three screenshots of what was going on. This is the first boss. https://imgur.com/a/XLoboOl