JIRA CSV Import does not import the Original Estimate values correctly. Why?

[Mark Hawkins]

I have an issue where I am trying to use the IMPORT CSV functionality against a JIRA project, to create issues and auto-populate their Original Estimate values. I have correctly followed the JJIRA formatting documentation here and here is a breakdown of my issue using screenshots: 

1. Import File: https://gyazo.com/3bb2e024fb72801a312b6e2b84563bae 
2. Board Original Estimate (after import) where I show what I expect to see as the values after an import: https://gyazo.com/e7b2d693c0b625d57f25a6f6f753e97e
3. My board settings: https://gyazo.com/861053e7fcb7d6a3cbe84e7864f3c47e
4. My Global Time settings: https://gyazo.com/d361b1f2a8546ead908e36ffb2a06ba3

My global work hours per day are 8hrs. As an example, I tested in this CSV import, where the original estimate value = 9000 seconds, yet after it imports it shows 2h against the Original Estimate field in the issue, instead of 2h 30m. In the same import file it successfully imports 18000 seconds as 5h.

Can anyone help advise why JIRA is incorrectly importing the original estimate data?

Thanks

Mark