Nexus 5X Nougat 7.1.1. Update: Memory Hog

I just updated my Nexus 5X phone with the official OTA 7.1.1 OS. I had about 16.8 GB memory used out of the 29.12, but since the OS updated, it's gone up to 20.19 GB! That's a loss of 4 GB...what the hell, Google?

I rebooted the phone, same issue. What's happening and how do I fix it? (please don't say reset the phone...)

Thanks.