Currently I am receiving emails with attachments that were sent anywhere from 30 minutes to 2 hours ago to my Microsoft Teams Channel. It seems that they are out of order and this is the first time I have encountered this. I've looked into size requirements and I don't believe that is the issue. The senders of these emails shows that it was successfully sent as they are in the 'sent items' in their inbox.
If you can please let me know what might be happening and if I am able to prevent this from happening again.
The email to channel functionality uses a "phantom" tenant to route the messages, and we have pretty much zero visibility of what happens there. If might be that the different attachments take different amount of time to process for anti-spam and anti-malware checks, or it might be something completely random. There's really no way for us to know as we simply don't have access to that "phantom" tenant in order to run troubleshooting tools. You can open a support case and request more info.
I've seen such delays with regular, no attachment mails as well, and overall my experience with the feature has been on the negative side. I would suggest finding another solution if possible, for example using Flow to save the attachments directly into some SPO library, etc.
Best Response confirmed by
Kristen_100 (Frequent Visitor)