One oddity that I've come across is that Field Manual: Draconis Combine p. 65 states that the 19th Galedon Regulars were formed "during the long-drawn out Second Succession War", from soldiers of questionable loyalty. That conflicts with Historical: Reunification War, which has the 19th deployed as one of the four regiments of Galedon Regulars within the Combine Auxiliary Corps, supporting the SLDF invasion of the Outworlds Alliance - see p. 141 and various other pages. Has H: RW effectively superceded FM: DC, or was the 19th disbanded/retired/wiped out at some point during the Star League era or First Succession War and then reformed?
I hadn't paid much attention to the 19th Galedon Regulars before, but I've got to say they have one of the best unit insignia I've ever seen!