I have a project with 39 loop regions and performed a batch export to produce 39 separate bits of footage. The problem is, Vegas 17 hasn't split the regions very accurately, it splashes up a split second of footage from the previous region before starting the current one.
If these are video loops, try enabling Quantize to Frames under the Options drop-down (Alt+F8) and make sure all your region markers are on a frame boundary.
Yes, Quantize to Frames and Snapping turned On. and Project Frame Rate matching your source. But it won't help your current project unless you drag each event by hand or use a script, such as Vegasaur.
Probably better to start a fresh project with the correct settings and re-introduce your Media.