I made an errata report back in 2016 about the M42B as listed in the Infantry Tables v3.0, and have not seen a response.
It appears the listing of the M42B there combines the Standard and Light Machine Gun modes of the weapon as described in A Time of War, as it does both 1.08 points of damage (implying it has the Compact Grenade Launcher) and has the Heavy Burst special (implying use of the Light Machine Gun mode, which is the only mode of the weapon that qualifies, but doesn't have the Compact Grenade Launcher).
The issue is that the weapon is listed only in the "Standard" weapon section of the table, and is thus the only "Standard" weapon that has the Heavy Burst special.
Was this intentional, or just an oversight?
EDIT: Further research as revealed that Sarna cites a 15 round burst for the Standard mode, possibly sourced from Handbook: House Davion. AToW was published after HB: HD, so the 10 round burst for that mode from that book should trump.