OneDrive file request feature - no notification sent when a file uploaded

[Curt Kessler]

We've been using the request files feature in OneDrive for a while now and it was just what we needed. Sometime in the past little while (weeks?) OneDrive no longer sends an email when the requested file is uploaded. I've checked the SharePoint notification settings, all fine, and as I said, it was working just fine, then stopped sending. I've looked through the email logs for the whole company, it's not even trying (no blocks, junk folder, quarantine, etc.) it just stopped working. 

Has anyone seen this or know a fix?

[#2]

@Curt Kessler 

How about message trace so that we can make sure Email deliver to you tenant or not at least

[#3]

I ran trace logs in Exchange for the past two weeks, there weren't any (no blocks, quarantine, junk, etc.). I did another test and after about 10 minutes I got notified in the test. I did have one of our users report this again and did a trace, no attempts. It seems to just be spotty as to if it sends anything.