Attachment in iOS mail app behind html content

Hello everyone,

I'm facing to an issue that an attachment to an e-mail that I sent is not correctly displayed in my inbox on an iPhone X (iOS 12.1.4). The attachment is positioned behind the heading of my html content, so it is sometimes hard to open it when there are several attachment files. Is there a documentation for how to style an html mail with attachment to really "attach" a file at the end of a mail?

In other mail clients like mail app on MacOs it is displayed correctly.

Here is an example of that issue:

https://imgur.com/a/oPGKaIh

Thanks for any advice.