The R12_c3 release fixes a bug that prevented Text, Attribute, and Attribute Definition entities from referring to any more than 256 text styles; although more styles could be created, entities that attempted to refer to them would in fact get some other style. Such situations arose most often when XREFs were being used.
The fix doesn't affect existing drawings in which text style references are already confused, but it works well in the case of XREFs, if none of
