Nothing really new there, the original M16a1 had its share of malfunctions and jamming in Vietnam. Many squads were caught with their weapons taken apart while they performed maintenance.
The M16a2 also had its share of problems, especially in that huge sandbox.
As a matter of fact, anything with lots of moving parts and OHT or any other lube will just attract sand, dirt like moths to a flame.
These weapons require lots & lots of care, you take care of your rifle and your rifle will take care of you.