SW PDM Pro, Task Notification emails sometimes are not received

Hello Forums,

We are using PDM Pro & SW 2022.  We use export tasks in our workflow and have them run on a dedicated "task server".  I have the tasks set up to send the initiator of the export an email either for success or failure.

Sometimes, the task executes but the user never receives any email.  There's nothing consistent, just randomly 5% of the time no email.  No the emails aren't going into junk (unless perhaps the server is rejecting them, but seemingly at random?).

I've reached out to our VAR but they've been no help (because we can't reproduce the issue, ever) and it doesn't happen often enough, nor are the consequences severe enough, to warrant forcing the issue.

Has anybody else experienced this? Any ideas where to look for a root cause?