That's what I thought initially, that they're falling back on the Halbs because of the weak lower wing fiasco, but we didn't get the Alb D.III's yet and it's a few months too early for that. The weird part is I got to keep my Alb D.II and they got stuck with Halbs D.II's despite the availability of Halbs D.III's and their ranks being high enough to get those. Never've seen that before.
Yes. Plane assignment (whatever the issue above, if there even is one, aside) can be a little "funny" as you mix Jasta HA's, you, and new/replacement planes. Least as of several patches ago - have not been in the position to see recently.
Back in the day, when your Jasta received a partial re-equip of newer planes, the HA's present - even if they had 0 victories or were brand-new, would get the new plane while you, the 12 victory ace and salty dog, would continue in the older aircraft till a set date (usually when the whole unit should have them) even though the unit has 4 or 6 of the new planes in reserve.
Minor issue but a Campaign Editor would fix that real quick.