I had that, too, in a career several months ago, before upgrading to 1.5. I can't recall the game date exactly, but I think it was later than yours. Those superimposed merchants really looked strange, a bit like Siamese twins.
I never found out what really caused the oddity, it may have been a career mission being saved while submerged, which is known to cause glitches. I remember though, that in the same career there were often strange colored smoke puffs above the water in the wake of the sub when starting a saved career game.
I ditched the career, made a fresh install (actually several parallel installs) and never had those probs since. Never saving submerged anymore.