Observation Dates missing from project check list download

Please fill out the following sections to the best of your ability, it will help us investigate bugs if we have this information at the outset. Screenshots are especially helpful, so please provide those if you can.

Platform (Android, iOS, Website): Website

App version number, if a mobile app issue (shown under Settings or About):

Browser, if a website issue (Firefox, Chrome, etc) : Chrome

URLs (aka web addresses) of any relevant observations or pages: https://www.inaturalist.org/lists/560101-NNHP-Track-Lists-Check-List.taxonomic.csv

Screenshots of what you are seeing (instructions for taking a screenshot on computers and mobile devices: https://www.take-a-screenshot.org/):

Description of problem (please provide a set of steps we can use to replicate the issue, and make as many as you need.):

Step 1: Download project CSV or taxonomic CSV.

Step 2: Open CSV in Excel

Step 3: Species have blanks in first_observation and last_observation but observations are present in project. (Highlighted rows in above screenshot.)

There used to be a radio button to find taxa on the project list that had not been observed:

This is now missing so I thought I could find the same information by looking at the CSV observation columns but many of the rows with blanks in this column actually have observations in the project.

Is there currently any way to find species from a checklist that haven’t been observed?