How will an EB-5 application affect A-1 visa status?

An EB-5 application will not affect your A-1 visa.

It should not affect it until you get to the final green card stage of the EB-5 - then you switch to permanent resident and not A-1.

Filing an I-526 petition will not provide you with any lawful immigration status in the United States and will not directly impact your current underlying nonimmigrant A-1 status. However, holders of A status are ineligible to adjust status in the United States (i.e. filing a petition for a conditional green card upon approval of an I-526 immigrant petition) unless you waive privileges and immunities on Form I-508.

The fact that you filled an application should have no effect on your current status. When your application is approved, then you will need to adjust.

You will not lose your current visa status simply because of your application for an investor-based visa.

If and when you file an EB-5 investor petition on Form I-526, it does not directly affect your A-1 nonimmigrant visa as a diplomat as far as the United States is concerned. You will still be eligible, provided you have the support of your foreign ministry, and you will still be eligible to have a visa issued and still be eligible to be admitted in A-1 nonimmigrant status. No, your passport will not be taken nor will your A-1 visa stamp be cancelled when you file an I-526 EB-5 investor visa petition. While anything is possible, it would be very unusual for the U.S. Citizenship and Immigration Service to inform your home embassy. The only people that are informed will be the U.S. officials such as U.S. consular officials and U.S. immigration officials that would have access to a database showing that you filed the I-526 EB-5 investor petition.