I've been using FF for almost a year now, utilizing push notifications in both actions flows (trigger push notification) and scheduled tasks in Google Cloud Functions and they have been working flawlessly.
Recently, namely after the 4.1.85+ update, they have been a hit and miss. Sometimes they work, sometimes they don't. I'm not sure if this is a FF issue or a Google issue, but something is definitely is not working properly.
For example, in a workflow, user A submits something that needs to be completed by user B, in that action flow, after creating or updating a document, I trigger a push notification for user B, after that it goes to user C and notifies both C and A that B has finished his task. This used to work fine, now they can either all work fine (which is the intended behavior) or one of the users doesn't get notified or all of them don't get notified, as I said before, a hit and miss.
As for the second case, which made me question if it's a Google issue, I have some Google Cloud Functions that run on a schedule to notify users about upcoming events and such, these target all users or at least a good segment of them, again it's a hit or miss, the targeted users use both Android and iOS devices, so it's not a platform dependent issue.
According to the Google Cloud Console logs, the scheduled tasks run successfully without errors, which is making me really not sure if it's a problem on Google's end or a FF issue where the app doesn't receive the push notification, and when i manually run the tasks they run successfully and sometimes users get the notifications and sometimes they don't (all get it or all don't get it).
I've looked everywhere for a solution, on the FF forums, on Google support, I can't seem to find anything related to the problem I'm facing, and this problem is making the app unreliable cause users are in the dark and are not aware of the tasks awaiting them.
TL;DR
Something is wrong with the push notifications as of late, they have become unreliable either using the action "Trigger push notifications" or through Google Cloud Functions scheduled runs.