I have exactly the same problem with Contact Form 7. I have created a custom consent with name “acceptance-283” and in the contact form 7 settings I use [acceptance acceptance-283] By using this form you agree with the storage and handling of your data by this website[/acceptance]
Then for testing I use the contact form to send a message using a specific email address. If I search then for this email address in the Data Subject it doesn’t find any data.
By the way, everything works fine with comments. If I leave a comment with a specific email address, then retrieving data for this email works fine in the Data Subject tab.