Hello. I just completed the Assault on Stormreach series of 4 quests (ending in Siegebreaker) and was looking for a Mark in the chests/ reward list. Unfortunately I didn't find it. According to the wiki,
NOTE: Named items that can appear on this quest arc's end reward list will have a 100% chance of appearing on every third completion of the story arc.
This adventure pack contains 2 groups of quests, the first 3 seem to be their own story arc.

And these 4 - Assault on Summerfield, Blockade Buster, Undermine & SiegeBreaker (SB) seem to be another arc. The wiki also says that 3 of these 4 can be completed initially in any order, but must all be done to 'flag' you for SB. My question is this: once I have flagged myself for SB, do I need to repeat the other 3 quests to get the Arc End Reward 100% option or just SB? If I do need to complete them, do they have to be done before I repeat SB? As far as I can tell from the npcs, once I have completed the chain the first time, any of the 4 npcs will allow me to repeat their quest regardless what else I have repeated.

If you have repeated this chain and gotten the chain reward list again, please share your experiences. Thank you in advance.