PE Case Study Issue: BS Cash and CFS End Cash don't Match (Financial Modeling)

Hi, so I'm working my way through this PE case study. They have given me a large QoE report file with a list of things for me to do. One of the things they asked me to do is build a CFS for the Last Twelve Months (LTM). Given that the QoE report has both an IS and BS, this seemed like a pretty straight forward task. The IS and BS are in monthly periods from Jan-18 to Sep-20, and while I hadn't seen monthly periods in IB/PE case studies before, that shouldn't really matter. Well, I built out my CFS all the way to the bottom without issue, until I compared my ending cash balance with the cash on my BS: it's off...some of the months by a significant amount. I tried reworking through all the different parts of the CFS to see if I made a mistake, but the ending cash still doesn't match BS cash for those same periods. I am stumped. Not sure if I made a boneheaded mistake that I can't find, or if I'm just a moron in thinking that BS cash and endings CFS cash always need to match (99% sure they do). Any help or pointers would be greatly appreciated.