Fought with kakashi, and my chakra is carrying over fine (85 from round 1 to round 2)

Just to be clear, the way that chakra carry over works is like this: At the time that your chakra normally refills, if you have MORE than what is supposed to be refilled, you keep whatever it is that you have.

If you have, for example, 30 chakra at end of round 1, you will be AT 40, not get 40, AT 40.
If you had, for example, 100 chakra at SOMEPOINT in round 1 but uses 60 of it so you only have 40 left, you will be also AT 40 at round 2.

Kurenai is a rather meh chakra generator for round 1&2 mostly because the ENEMY also have low chakra, so it won't absorb much. So it's rather unlikely that you have MORE than what you should to begin with. (note that kurenai CAN get excess amount in 3v3, thou if she uses her jutsu, unless there are other chakra generators, she won't have >40 to carry over)

Without knowing exactly what happened, I won't be able to say whether you saw a case that does not follow the "rule of chakra" or not. You will need to describe the battle(s) in more detail.

Or you could have been running another chakra generator that you aren't aware of, so that your chakra have always been 20(base)+20(other generator)+whatever kurenai absorbs.
So ALL of that would be kept because it was over 40, and what you end up "seeing" is 40 plus whatever kurenai absorbed, as the others folds into the 40.

Now, the most common early game chakra source is kakashi clone, if that dies on round 1, what I described exactly would happen. There are, of course, others, including some talents on the various mains can generate chakra.
So the question is, what team were you using before and have you changed anything, ninja or talent, lately?