Slitherine

For some reason they still don't get this bonus in patch 1.04. Was this intended to be fixed but forgotten?

Yes that's intended. You still get the Hellenistic additional buildings, but you are not Hellenes enough to warrant the modifiers. Lysimachos drew heavily on Thracian people and the Seleucid empire for its big part was made of non Hellenes (except the elite).

As the modifier "biggest footprint" is a limitation of manpower, it is not added to them. You thus also lose the 15% Culture and 10% Commerce.

OK that sort of makes sense, but why do Ptolemy and even Bactria get it then?

at a guess, both were more 'Greek'. Both regions had a long history of Greek migration and Hellenes both in their military and civil populations. Egypt started using Greek mercenaries around 650 BCE and there was a sizeable Greek population in the north at the same time. Similarly Bactria was settled by Greek veterans by Alexander but by the time it broke from the Seleucids it saw itself as very much a Greek polity.

Bactria had a very interesting story about its Greek population. Not only Alexander settled veterans, but being the backyard of the Persian empire, the prisoners of wars were also sent there. I think there is an interesting video on youtube on Bactria from one of the historical chanel there.