Yes, another sand-through. Tell-tell sign is very shinny spots and very dull spots next to each other. Most people do not realize how thin the coats are when placed on the blank with paper towel. The layers are very thin. Not much build up as believed, even with 6 to 10 coats of thin, medium or thick - when applied with paper towel. Paper towel absorbs 75% or more and wipes more off than it leaves on. If the build up is a tad uneven or rough, then 1/2 or more will be sanded off to get down to an even layer.
This is a time to get a good set of calipers. Measure the blank at different points after it has been turned as much as you are going to turn it. Write those measurements down. Then apply the CA with paper towels (as most people do.) You will find that you are not getting as much build up as you would think, especially after you sand it.
The next problem to look at is this: In many cases, there will be more of the shine removed on one side than the other. If it is consistent in the dull spots rather than more to one side, then your mandrel is not a problem and your technique is good. IF it is more on one side than the other, then you are having a problem with the mandrel in some form. (Several possibilities in this case, all mandrel related.)
I don't think this is a factor in your case after seeing the picture, but yes, temperature does affect the finish, not so much on the shine, but the curing time and sometimes white spots or clouding - if high humidity is present.