The Swarm Begins[1] is missing the Alliance counter part of the quest line in order to obtain the quest (currently only the Horde variant is shown that ends with For Family[2]). In order to proc the breadcrumb Warn Stoneplow[3] -- which is correctly listed without any prerequisite, you must complete up to The Waters of Youth[4].

[1] https://www.wowhead.com/quest=30622/the-swarm-begins
[2] https://www.wowhead.com/quest=30174/for-family
[3] https://www.wowhead.com/quest=30360/warn-stoneplow
[4] https://www.wowhead.com/quest=30445/the-waters-of-youth

Fixed

Ok got it thanks!

@ImUnicke [4] is the missing Alliance pre-quest for [1] (with [2] being the Horde version that is already listed).

[3] is already listed as a breadcrumb for [1].

@kallesommernielsen
Sorry I'm not quite following this explanation, so you're saying that [1] is missing alliance pre-req, but which quest is the correct pre-req? [3] or [4]?