So, I recently noticed that depending on which Linux machine I was running, valgrind would throw a solid 90k errors, for the exact same file/code that threw no errors using valgrind on a different machine. So, I looked into it, and it looks like while one is running valgrind-3.7.0, the other has valgrind-3.15.0. sudo apt update/upgrade didn't show anything, and reinstalling didn't make a difference. (For reference, I am using Raspbian on one and Ubuntu on the other)
Now the question: Why are packages installed with different versions on different distributions? Would it be advisable to manually install the newer version on a distro that defaults to an older version? If so, what is the easiest way to do so?