Validate step in server connect

I have a form with a text input, I have a validate step in server connect linked to the form field.

When i enter a value that is already in the database, the action stops as it should and the source code validation for the field shows correctly except it does not show because the input class does not get is-invalid added to it.

Can anyone think what I may have done wrong.

Here is a screenshot of the source code after i submit the form with an invalid entry

Screenshot 2021-05-11 at 14.41.02844×192 41.3 KB

If I manually add the additional class to the input of is-invalid then i see the message.

Screenshot 2021-05-11 at 14.45.072858×1126 491 KB

I have temporarily added this to the input so it works for now dmx-class:is-invalid="status == 400"