Scorecard for Record Count Differs from Data Table with same source data

[cgil1]

I created a dashboard that aggregates participant feedback data from a google form response sheet. I created a scorecard to show the total number of responses on the form with a null filter to only count rows with data. The scorecard matches my raw form data, as shown below.

The table beneath the scorecard is powered by the same data set, but only displays 1260 responses. 

The table doesn't have any filters applied, and when I tried to troubleshoot by adding the metric "Record Count" with a summary row, it will only show me the total number of rows in the sheet, 4999. 

Can anyone help me determine what's going wrong here? I tried exporting the data displayed in the looker table to my raw data to see if there were any trends in what was missing, and there doesn't seem to be a pattern. Thanks in advance for any assistance!