We think that this problem was limited to beta versions 3.1.8 through 3.1.10, but we want to make sure.
Assuming you're using auto-rates, do you see it subtract and re-add all of the rates with identical descriptions? It would show duplicates of all previous auto-rates with negative quantities, then another set of duplicates adding them back in. This doesn't affect the total but can be a real mess on receipts.
This may happen automatically if you have it auto-recalculating charges, but you can also check for it by going into any reservation's transactions and clicking "Auto-Calculate" multiple times. After they're added once, it should not add them again.
So far we've seen two definite cases of this, but it only seems to happen on certain computers (the Windows version doesn't seem to matter). We can't reproduce it here, and in one place it only happens on one of their networked computers. It might be related to Celeron processors, but that's not confirmed.
In any case, please let us know whether or not you see this, along with which Campground Master version you're using and what type of computer/processor you have.