I've never seen a CMH lamp like this before.
It appears to have a hybrid design of arc tube with one half featuring the traditional squared end of the early CDM lamps and the other half having the formed arc tube profile of the modern lamps.
Forming the latest ellipsoidal shaped arc tubes is extremely expensive, the most being the single piece arc tubes and to a lesser extent the two-piece designs.
GE’s design here is cheaper and slightly better way of doing it. It is still a two piece ceramic but the interface is shifted off-centre to one side. This makes assembly very much easier and cheaper, and being asymmetric has the advantage that when used base up the thermal profile is actually better than an ellipsoidal arc tube, and performance can be slightly improved.