Hi Matt,
If the status bar shows in some tab, I think it more likely that it relates to the data. Could you do the following test to narrow down the issue:
For the tab that won't show the status bar, right-click the worksheet name, copy one of them to a new workbook > select the data and clear the format(Home tab > Editing group > Clear > Clear Formats ) and see if the status bar shows. You could also open the status bar menu uncheck the Sum and check it again see if it make any changes.
Another test is copy all the worksheet and use paste special (wight click > Paste Special > Values) to paste them as clean data then see it the status bar shows up.
If it's acceptable, could you share a copy of the workbook? So that we could test from our side to see whether it relates to the file. To protect your privacy, you could share the workbook via PM: Private Message.
Also, there are still chances that the Excel program is broken. May I ask whether you see this issue in other workbooks?
If it's an Excel issue, you could try Repair Office first: Repair an Office application
We also need the following information in case it's an Excel issue:
The Excel version you have (File > Account > About Excel)
The Windows version you are using (Press Windows key + R > input winver)
Regards,
Alex
[Updated by Alex Wang MSFT, UTC 4:33 AM 01/19/2019]