Three sightings in the same spot is significant - that's not your eyes playing tricks, that's a pattern. Residual haunting would be my first instinct, like something's worn a groove into that location. Could be an old pathway or threshold that predates the building itself.
That said, shadow figures are a bit different from your typical residual activity. In my experience they tend to have presence - you get that prickly awareness they're aware of you too. Did it feel passive, like a recording on loop, or did it react to you being there?
I've had something similar in my old place in Staffordshire - same corner of the landing, three or four times over about six weeks. What finally convinced me it wasn't a trick of the streetlight coming through the curtains was that it appeared once at 3am with all the blinds shut.
A few things worth trying:
Log the times precisely - patterns in when as well as where tell you a lot, Drop a cheap EMF meter nearby - the Cornet ED88T is decent for the money, Note your own state - stressed, tired, relaxed? Emotional state can act like a signal
The interdimensional angle interests me too. Some researchers argue shadow entities exist slightly out of phase with our reality, which would explain why they're dark rather than luminous.
What's the history of your property? Even 20-30 years back can be relevant. And has anyone else in the household clocked it, or is it just you?
