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.

Did you end Round 1 with less than 40 chakra?

How the chakra works is that in order to start Round 2 with more than 40 chakra, you need to end Round 1 with more than 40 chakra.

Scenario 1: End Round 1 with 60 Chakra. Starts Round 2 with 60 Chakra.Scenario 2: End Round 1 with 20 Chakra. Starts Round 2 with 40 Chakra.
Scenario 3: Used initial 20 Chakra from Round 1. But managed to get 20 more at the end of Round 1 to end the round with 20 Chakra. Still starts Round 2 with 40 Chakra.

So basically, Round 2 start is default at 40 Chakra unless you have more than 40 Chakra left over from Round 1. The same applies from Round 2 to Round 3. Round 3 starts with default 60 Chakra unless you have more than 60 Chakra left over from Round 2.

Thank you for the quick replies.

Before today any chakra absorbed would be added to the next round's default amount but the interaction today left me at a loss as it wasn't the one I have been observing in the past few weeks I've had her.

Even if she absorbed 10, I started round 2 with 50 and then kept adding on that.

In a few instance battles earlier she absorbed 20 extra chakra in round 1. Usually I've seen this extra chakra added to the next round's total if not consumed.

Maybe I was seeing a bugged mechanic before this and now I'm just a bit confused.

But both of your replies on Chakra make a lot of sense and perhaps what I was seeing before was an odd unintended interaction.

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?