Agreed, having the spike happen for everyone does point to something happening on the machine, more than something a user did.
The only user action I can think of would be something like one person creating a file in an area that everyone else had a window/tab displaying, and that file causing high memory use while it was inspected by each person. (The temporary memory spike for that is unlikely, but not impossible, especially when factoring in third party components, antivirus, etc.)
If it was notifications queuing up, it seems to fit with other things we’ve seen, and hopefully Jon’s change will improve things there. Either way, it’s worth knowing about as another part of the puzzle. Thanks for spotting it and letting us know.