Has anyone else had this issue when using Tidy Cats litter?

We have three cats and are constantly buying kitty litter. We’ve been using Tidy Cats for years without issue, but recently we’ve been finding clumps of feces and urine cakes in new containers of litter.

We normally use the large plastic containers but after two of them had used litter inside them, we switched to the large cardboard box and lo and behold, when I got to the bottom of the container there were multiple urine cakes and pieces of feces.

At first we thought we were mixing up old and new containers (we usually keep an empty plastic litter container to empty the old litter into), but there are only three people responsible for the litter changes and all of us make sure to set the dirty container aside until we need to take them to the trash, so it has to be the new containers. What should I do?