Sometimes the Splinter grenades and plasma grenades do not spawn when you spawn while having the armor mod on, same counts for the upgraded shield sometimes and other armor mods.
My entire fireteam has these problems, so it is not my “crappy” internet.
And yes I respawned, so I didn’t put the armor mod on when I was still alive.
My friend and I are having this problem too. I use upgraded thrusters and upgraded sensors often. Sometimes when I swap from upgraded sensors to upgraded thrusters and then back, upgraded sensors - as well as any other mod I swap to, even if I swap back to upgraded thrusters - doesn’t work anymore for the rest of the match. Did 343 intend this or is this a major bug? I’ve haven’t noticed this prior to the Ghosts of Meridian update.
> 2533274921681623;2:
> My friend and I are having this problem too. I use upgraded thrusters and upgraded sensors often. Sometimes when I swap from upgraded sensors to upgraded thrusters and then back, upgraded sensors - as well as any other mod I swap to, even if I swap back to upgraded thrusters - doesn’t work anymore for the rest of the match. Did 343 intend this or is this a major bug? I’ve haven’t noticed this prior to the Ghosts of Meridian update.
I am pretty certain it is a bug, for players it can be resolved by switching armor mods and back, but sometimes that doesn’t even work
I have been having the exact same problem. Returning to the previous armor mod has not worked for me, and I am not able to ue any others 
It’s a known issue OP, you can see the following topic for a temporary workaround 
Warzone armor mod bug
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> It’s a known issue OP, you can see the following topic for a temporary workaround
> Warzone armor mod bug
The very next post sums up the outcome. It’s not a workaround at all