There’s multiple threads on this, and somehow none of them have any acknowledgement:
Anyways, here’s the response I got after reporting the issue:
I understand that you are unable to start the quest “Aspectral Invitation”. Let’s check that together, shall we?
Checking this matter, I understand that this is annoying. So, I looked around, and there is nothing that would cause this challenge to happen. Also, I checked with our tech team, and they informed me that they haven’t received any registered reports regarding this challenge.
Hence, I would highly recommend logging out and back in, and this might help it, as it was reported to fix this challenge.
If this doesn’t help, in order for us to get a full range/effect causes of this bug, I would highly recommend reporting this challenge on our tech forum, so that they can take a look into it, as they have the necessary tools to investigate this challenge. Also, any other players having similar experiences will be able to support and comment on that report, allowing it to reach our developers faster. Here are the steps on how to bug report for your convenience: https://eu.battle.net/support/en/article/000015043
I understand that waiting is never pleasant completely, as GM(s) can’t fix a mechanic that is not working properly, we need to bug report this. I thank you in advance for your patience and understanding, valued hero, and sincerely apologize about any inconvenience, as this challenge is being worked on at the moment, and will be fixed soon enough.
I hope that I managed to clarify the situation for you. If you have any further queries, don’t hesitate to reach us back, and we will happily assist you.
So seems that they somehow haven’t seen these multiple threads.