Even stranger, if I play out all the US departure points from USA, each gets access to differing dates of SEZ space. (due to invisible married segment rules)

October - USA-DXB-SEZ
IAH/IAD/LAX/SFO - 0 Space on the SEZ leg
SEA - 2 dates with J on the SEZ leg
DFW/JFK 1 Date with J on the SEZ leg

(I don't understand why it would matter what flight I take to DXB, to give me access to the SEZ leg)

What a...
great day I am having.