Ok so I noticed another odd bit of information today in the Decent of Angels
HH novel. So here's the excerpt:
[...] many were forced to discard portions of their armour as the xeno creatures' acid eructations melted their Mark IV plate.
So this was at the time of the war on Sarosh, which according to Lexicanum took place at some unknown date in M30. Now I might be wrong here but I was under the impression that Mk4 plate wasn't issued until around the beginning of the Heresy (004. M31).
So is this another canon issue? Or is it possible that the Dark Angels (who I actually though kept older plate armour) already had the Mark 4 armour?
Cheers in advance for your thought s and opinions,
BP