We don't really know, it is possible that slots can be rigged.

Playing slot (in general gambling)mean taking responsibility of every outcome, that is the reason we monitor what kind of slots we play. RTP isn't also trusted but can be considered while playing any slot.

Slot has always been about probability, we can't tell from players perspective (since the house is always ahead) only the owners are aware of the scene behind, if they manipulate slots it's really difficult to tell, we can only assume after consecutives losses and similar complains from other players.