I've been importing Google fonts into emails successfully for a while now. In developing a recent email, I noticed that one of my Google fonts (Prompt) is being italicized whenever it is set to bold in Apple Mail. This is really odd - no other email client renders it as italic, and I have confirmed that the source being displayed in Apple Mail does not have any additional styles or tags that could be forcing the italics.

I am using Apple Mail 10.3 on iOS 10.12.6.

I've been importing the font using link in the header (wrapped in a MSO conditional so that Outlook doesn't default to Times):

<!--[if !mso]><!-->
<link href="https://fonts.googleapis.com/css?family=Oswald|Prompt:300,400,500,600,700" rel="stylesheet">

Has anyone else run into this? Have any workarounds/hacks/fixes been found for this?