Retrieval using "firstpublished" endpoint returns inconsistent results

[darrenparkinson]

Describe the bug
A clear and concise description of what the bug is.

This Advisory has a first published date of 7th February 2024. https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-expressway-csrf-KnnZDMj3

However, when I request this via the API for the 7th, it is not returned. When I make a request for the 8th it is returned. This appears to be because the data in the API is not the same as the data on the website?

To Reproduce
Steps to reproduce the behavior:

1. Browse to https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-expressway-csrf-KnnZDMj3
2. See the first published date of 7th Feb 2024 at 4pm GMT
3. Make API request to https://apix.cisco.com/security/advisories/severity/critical/firstpublished?startDate=2024-02-07&endDate=2024-02-07 -- this does not return the data as expected
4. Make API request to https://apix.cisco.com/security/advisories/severity/critical/firstpublished?startDate=2024-02-08&endDate=2024-02-08 -- this does show the PSIRT, but isn't expected

Expected behavior
A clear and concise description of what you expected to happen.

I expected the first published date not to change?

Screenshots
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