Depending on the company, "major" can be used to mean a number of things, such as visible and painful customer impact, or significant revenue impact.
Based on the description of the outage (issues serving new ads to Messenger), it reads like the latter.
> We are currently investigating an issue where creating new ads with app_destination as MESSENGER results in the following error ...
Admittedly if it does have significant revenue impact, I'm surprised that change hasn't been rolled back or otherwise mitigated in the week+ that the incident's been open. Or maybe it has, and nobody remembered to close the incident.
Based on the description of the outage (issues serving new ads to Messenger), it reads like the latter.
> We are currently investigating an issue where creating new ads with app_destination as MESSENGER results in the following error ...
Admittedly if it does have significant revenue impact, I'm surprised that change hasn't been rolled back or otherwise mitigated in the week+ that the incident's been open. Or maybe it has, and nobody remembered to close the incident.