First, [welcome] to the FOG! Sorry your first post had to be about a problem, but I think we can help you out.
The ETS sanders are known for being 'smooth as a baby's bottom', so your experience certainly isn't normal. You didn't state if the sander was brand new or just 'new to you' but I'll assume that it's brand new. If that's the case, you might simply have gotten a bad one. Although it's rare, it does happen from time to time.
The first thing you should do is contact Festool service and talk to them. Based on what they say, you may have several repair options. None of which are likely to cost you any money. And if you purchased it within the last 30 days you can return it to your place of purchase for refund or replacement with NO HASSLE.
If you have ANY problems getting your dealer to help you out ( you won't! ) report back here and you will be assisted.
BTW, I speak only as an 'unofficial evangelist' - not as a formal representative of Festool - but I am so confident in their support that I do not hesitate to say this. They want you to be 100% pleased, and go out of their way to make sure it happens.
Again, welcome - and good luck!