This is somewhat of a general rule which is misunderstood, but I have noticed this error on a painfully large number of analyses - even a few GP members are getting this wrong on stuff I GP. This is concerning the usage of the comma before while. It should be used only in situations where contrast is being expressed. For example -
Ferrothorn OHKOes Quagsire while also setting up Spikes.
Ferrothorn sets up Spikes, while Heatran sets up Stealth Rock.
As I said earlier, this is somewhat of a general English grammar rule, but given the regularity of such a mistake being committed, I thought we could probably make this a standard.