The 025 has a automatic on for 20 minutes on start up whether you have reached your set temp or not. If you have her set for 200 and it's only been on for 10 minutes it's going to keep raising the temp until it hits it's 20 minutes, that is to get the wood smoking. 300 seems a bit high I don't think mine has ever got that high on a start of a cook but if you by chance shut it off and restart it, it will do the same 20 minute heat up as if it was cold.
In the end I wouldn't worry just yet. Get that smoker filled with some meat and the temp should control itself better than when empty, and you will also find the more it gets seasoned for some reason it holds it's temps better. It just likes to get used I think.
If by chance you still have a problem check your temp with another thermometer and if it's still not right call service, they will make it right in quick fashion.