Battletech has done similar things over the years, with many capital ships getting at least one refit (block II variants), although the art problem between two of the technical manuals has arguably muddied some stuff over the years.
Basically when the
second one was written, they couldn't find the art resources used for the
first one and had to design entirely new art from scratch. This annoyed some fans because some of the designs (like the
Black Lion; the newer Clan model is bottom center) don't look like a logical variant of the original, although mechanically they're not that different. Others like the
Cameron and
Sovetskii Soyuz designs do seem more plausible as refits, at least to me.
Part of the problem is that, in-universe, it's not clear when the Block I designs were replaced by the Block IIs in production. The Exodus Fleet which eventually evolved into the Clans has been variously depicted as using mainly 2750 type ships in one book and mainly 3057 ships in the companion book, even though they're part of the same set and written long after the tech books were published. So it's not a transitional issue as occasionally happened with the art in some of the early Clan books.
It's generally more common with mechs or vehicles, as those are sometimes direct updates of older units (like the original
Marauder II) and sometimes more modern descendants of vintage designs like the
Enforcer III. Many Clan variants of older Star League mechs as referred to as
IIC models, although in many cases these have had significant hardware upgrades with Clan technology. Most standard vehicles will keep the original name and simply have newer series numbers to reflect variants and the incorporation of more modern systems, or will have a letter designation for omni units that carry modular equipment.
