I noticed (and fixed) this problem twice now (in #1806 and #1799), so I went to investigate where it went wrong.

It seems like that commit 077be60 4 years ago introduced some (but not all) wrong prerequisites for some reason unknown to me. Not sure why it went unfixed for so long. Somebody more informed needs to check why this happened and if more quests are affected and need to be fixed.

For example, in WoWPro_Leveling/Horde/70_70_Crackerhead22_Shadowmoon.lua the following changes happened. I verified them manually:

• 10569 got added as prerequisite for 10760, but both are the same quest only first version is for Alliance, second for Horde (fixed in #1799 a few days ago)
• 10759 got added as prerequisite for 10761, again these are similar quests on Alliance and Horde instead. (not fixed as of today)
• 5 other prerequistes were added around and in between the above and are completely correct
• Further down for example 10597 got correctly added as prerequisite for 10598 even though this also has an Alliance counterpart in 10564, but this time no confusion happend.
• A bit more further down, another error happened when 10680 got added as prerequisite for 10681, which are again Alliance and Horde versions instead (fixed in #1806 just prior to writing this)
• I did not continue to manually check all of this file nor any of the other 20 files modified in this commit nor any other commits around that time 4 years ago.

For future comparison I added a green OK or a yellow NOT OK mark to illustrate the first few cases:

I find no easy way to verify and correct these in bulk, as both right and wrong changes seem identical on first glance.