That’s odd. But try this: right-click on “process name.” Do you get a drop-down list where you can select what columns you want to display? Mine starts: “Process ID, User, %CPU, CPU Time, %GPU, etc.” Towards the bottom you should have “Bytes Written.” Check that. Or does that already have a checkmark next to it?
Under the View menu there is a “Columns” item. Make sure all the important columns are checked.
Or, yeah, you could look there for the same options. 
Perfectly normal. That column would probably be better named “virtual address space”. It is not constrained by physical RAM or hard drive space.