WCAG Contrast Error for First Option Value. in Firefox

While validating a Contact Form for WCAG issues from https://wave.webaim.org/ using FIREFOX, I found one issue especially in first <OPTION> tag under SELECT.

“Contrast Errors: Very low contrast”

Surprisingly, I found that the error doesn’t exist in Chrome or Opera Browser.

I have used a fresh installation of WordPress and default theme 20/17. I have checked in different theme also but it really shows Contrast error for the first OPTION tag.

I have included the code and in that code <option value=”Accessibility Service” class=””>Accessibility</option> shows the contrast error.

I have applied high contrast colour codes in both frontend text and backend but it didn’t work either. Same Error.

`
<select name=”item_meta[14]” id=”field_pb5kp” placeholder=”Select Subject” data-reqmsg=”This Subject Field Must Be Selected.” aria-required=”true” data-invmsg=”Subject is invalid” class=”auto_width” aria-invalid=”false”>
<option value=”Accessibility Service” class=””>Accessibility</option>
<option value=”Proposal Request” class=””>Proposal Request</option>
</select>

Please Suggest.