Its just software related. I think it must be cause Vodafone calls it 4G in the EU that Vodacom gets the same carrier update or something hence its showing 4G.
MTN shows LTE always which I think is correct. On OS6 Vodacom was showing LTE but the update to os 7 and a carrier update made it show 4G. I wonder why vodacom is not fixing it.
I see that all the blackberry 10 devices that has LTE shows it as 4G for MTN and Vodacom but Windows phones like a Nokia lumia 1520 shows it as LTE on both Vodacom and MTN