As I understand it, the issue here is that two separate battery operated devices reported at about the same time, right? A contact sensor on the door and a motion sensor inside the room.
You can sometimes get false reports on multiple wired sensors if there’s a power surge. And motion detectors give “false” reports all the time–turning on the air conditioner can set off a roomful of sensors. Or a cloud throwing shadows.
But contact sensors are pretty hard to fool. They can get stuck on one state (open or closed), which is typically a reporting issue, not a sensor fail, but it doesn’t sound like that’s what you saw.
If indeed the contact sensor showed open followed by closed and the motion sensor showed movement in the same period, check the event logs to be sure nothing weird was going on on the server side, like time changes. Then it might be a server “hiccup.”
But if the logs look solid and you got reports from a contact sensor and a motion sensor at the same time, my vote would be that someone opened that door. It’s the contact sensor report that’s selling it for me. Assuming it IS a contact sensor and not a motion sensor or multisensor.
A vibration sensor and a motion sensor could both be set off by a big thump nearby, anything from a helicopter to a car crash.
But a contact sensor shouldn’t report open followed again by closed unless the magnet did physically go out of range. You can fool them occasionally into briefly reporting closed, but not opened then closed. And if one of the pieces fell off the door, that would show open, but it would stay open after that, not show closed again right after. And unlike a motion sensor, a contact sensor shouldn’t be affected by a spider crawling over it. So first check the logs.
FWIW.