Yes, that's bad. Not enough information to say much specific, though.
First, Reos are designed and meant for single battery use, not stacked
batteries. I'd guess that you had a bit of a tight fit getting two 18350s in there. There are some accepted uses of stacked batteries in various devices, but the Reo Grand is not one of them. I'd suggest looking up the manual on their site, if you haven't.
Stacking batteries, in general, is not recommended. Special care should be taken to monitor each one closely, and to wear them as evenly as possible.
At full charge, 8.4v / 1.1Ω = 7.64 amps draw on each battery. Hopefully they are at least rated for such a current draw, though that seems pretty high for the average 18350. At about 64 watts of power, you seem to be going down a path of 'chasing clouds' which could well put you and others in danger of injury and/or property loss if you don't know at least basic electrical theory and battery safety.
Basic to Advanced Battery Information from Battery University
Spending some time reading on that site would seem to be a good idea, as evidenced by the fact that you did not even mention a battery make and part number. Using the right type of battery, learning what your batteries are rated for, and staying well within those ratings, is essential if you want to go with high power vaping, safely. There are a lot of threads here about that subject. I'd suggest searching through a bunch of them, as there are too many issues and aspects to point out in one post.
