[Val'sharah] [All Nightmare Long] Lost in Retreat

[nagyajolet]

The following quests are part of the Val'sharah questline, All Nightmare Long substory.
This is not a repost, although the bug was fixed once, on 01-11-2017, but the issue still stands (probably broken by the 7.2.5 update).
Quoting from the closed report, for reference.

Quote:

For some reason, taking Lost in Retreat does not allow you to take Wormtalon Wreckage, and vice-versa. Those 2 quests should be allowed to be taken both at the same time, as they are side-quests once the player takes Dark Side of the Moon ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ I'd like to add that doing Lost in Retreat, then coming back for Wormtalon Wreckage, locks you out of Dark Side of the Moon. You basically skip ahead to the next part, which is "Regroup at the Refuge".

Order of quests, for reference:

1. Love Lost (ID: 41054)
Leads to the quests below.

2a. Wormtalon Wreckage (ID: 41707)
2b. Lost in Retreat (ID: 38671)
3. Dark Side of the Moon (ID: 41708)
These should be acceptable at the same time. Taking Wormtalon Wreckage locks one out of accepting Lost in Retreat.

The following should only be completable once Wormtalon Wreckage, Lost in Retreat, Dark Side of the Moon are turned in:
4. Regroup at the Refuge (ID: 43576)

Final quest:
5. Hearth of the Nightmare (ID: 38675)

Currently, completing Regroup at the Refuge prematurely locks one out of accepting or completing Lost in Retreat (might apply to the other quests, it takes too long to replicate as a player) thus making Hearth of the Nightmare unaccaptable.

Lost in Retreat, while flagged as such on WoWHead, cannot be shared. Probably due to Regroup at the Refuge flagging the character as ineligible.

In-game support refused to grant the missing quest or reseting the questline.
It's one of the requirements of the Legion flying achievement, thus cannot be solved by completing on an alt.
Please provide assistance ASAP.