I'm finding two troubling behaviors.
1) Sometimes workflows do not proceed beyond a Task. The Task shows complete in the Workflow history, but the workflow hangs. I insert a Log to History action right after, and the workflow never hits it. The workflow doesn't hit suspend, or any other distressed status.
2) Sometimes New Items don't trigger a workflow designed to start with New Items. This can be 1 in 10 or 1 in 20.
I'm sitting here with a nearly finished project that sometimes doesn't work correctly. I just logged 10 concurrent requests and got 10 of 10. But this morning I logged a single instance to show a colleague, and in a 15 minute show-and-tell one New Item didn't trigger the workflow and one workflow stalled out at a Completed Task.
I have a few tickets in with Nintex support (and one issue already identified as a bug), but I'd love to hear from anyone reading here who has found Nintex O365 to be 99.9% reliable, or a bit shaky at certain times?