As you have guessed, any text immediately following or preceding the asterisks ** should not contain any spaces.
If Airtable is incorrectly adding those spaces, then it is a bug with Airtable.
Please contact Airtable support to report this bug.
You can also contact Make support but they might not be able to do anything about it. You can open a new ticket, or if you are unable to login for some reason, you also can reach support using the contact form on the website.
If you manage to get your issue resolved with support, we’d still love to hear about it! Sharing your solution on the forum can help others facing similar problems.