This is a good question, and hard to answer without more specific research. Based as much on intuition and indirect reading as on anything measured directly, it seems the chances of such are significant -- that there are more likely to be more tars, if not also some level of increased chance of more harmful compounds released if any herbal material is heated to the point of significant blackening. However, the real question is "does it matter" -- ie, is this increased chance significant enough to be concerned about?
To make this more explicit, it would be necessary to be much more specific about a) what constitutes a "tar" and b) would it be considered potentially harmful to health. For example, the vapor itself could by most professional (chemical) definitions be classified as a "tar", and some people (more politically motivated) would also list it as "harmful to health" (most people (hopefully) know better). Thus, it becomes a matter of which polycyclic aromatic hydrocarbons and associated isomers are likely to occur and in what proportions as a result of any given level of overheating. As such, the overall question gets very complex very fast and admits of no simple interpretation other than the fairly obvious "significant overheating of herbal materials is generally bad".
As such, the best that can be realistically offered at this point is an unjustified opinion: as long as you do not heat herbs beyond the point at which more than about 15% of the load becomes more dark than dark chocolate brown, there is no cause or justification for worry. Beyond this, it is *probably* the case that even heating about 1/4 of a load nearly full black will have no detectable long term health effects as long as you are not doing so multiple times every single day for weeks at a time. It is also certain that even if you were to vaporize to these far limits, it is overall significantly less harmful than any type of smoking, including and especially that involving any amount of water filtration.
Furthermore and finally, as many people reading this are likely to already know, hundreds of politically minded groups have pressured many more scientists to find and publish any possible research supporting any connection whatsoever between smoking various popular herbs and any measurable/functional health defect or decline. Given such consistent efforts over the last several decades, the failure of any one of these very motivated and well funded groups to widely and dramatically publish any significant or well justified evidence, we suggest that it is safe to assume/believe that no such connection exists. Therefore, for anyone to spend any amount of time worrying about the possibility of harmful effects associated with occasionally somewhat overheating some 120 milligrams (max) of herb, given all of this, is probably unnecessary -- with a Launch Box vaporizer you are probably as safe as it is possible to be.