Yeah, I'd be contacting the RE. I've lived in 3 places while they were sold. We'd get 24 hours notice of people wanting to look through, never had the owners themselves come through. Never had others coming in to do things with out notice either.
Last year our place was sold purely as an investment property & the owner (also property manager) came through for pics, than arranged for the pest dude & inspesctor to come at the same time so we didn't have to deal with them twice