A related "gotcha" is not driving the gate hard enough. The 6A rating is also predicated on driving the gate hard enough to drive the on Rds to its minimum value.
I would be suspicious of this, in conjunction with inadequate heatsinking (i.e. heavy copper pads under the FETs) especially if the FETs are being driven by 3.3v. Looking at the specs, the FET is rated at 50mOhm given 4.5v gate drive - very acceptable - but if the FET is driven by 3.3v, it will have much higher Rds (may be running in the linear region which would be very bad). Note that the gate threshold voltage is 1.5v typical but 3v max so driving with a 3.3v logic signal would be marginal in the worst case situation.
I would be suspicious of this, in conjunction with inadequate heatsinking (i.e. heavy copper pads under the FETs) especially if the FETs are being driven by 3.3v. Looking at the specs, the FET is rated at 50mOhm given 4.5v gate drive - very acceptable - but if the FET is driven by 3.3v, it will have much higher Rds (may be running in the linear region which would be very bad). Note that the gate threshold voltage is 1.5v typical but 3v max so driving with a 3.3v logic signal would be marginal in the worst case situation.