It might be.
If those emails are staying on the Google server long enough to send a push to the iPad, it will download the email (if it's not too big) and give you a badge. These neither the badge nor the email will go away until you open Mail on the iPad and it syncs. Syncing takes a while, and it is often possible to open one of these emails before Mail gets around to removing them.
In the case of a normal email, the email will just disappear when the sync is finished.
In the case of a commercial or spam html email not everything get loaded immediately on a push. Pictures and other displayed content may remain on the Google server or the originators server until the email is displayed. If that material is deleted before you open the email, then that is the probable source of your 'no content' error.
Then, of course, it removes the non-existing email from your iPad.
If you want to test if this is happening try this.
Wait until you have some mail, according to the badge on the Mail icon, enough of it that you probably have at least one or two of these problem emails. Then go into settings and turn off your Wi-Fi and 3G (if you have it), so that Mail can not update. Open mail and examine what you can see, making careful note of what emails are probably spam or suspect.
Turn you wi-fi back on, and see what happens with those, and the legitimate emails.
