If its a bottom mount case with a bottom grill for the psu it should always be turned downwards.
That isolates the psu from the rest of the system.
Its pointless having it pointing up because in essence heat doesn't sit at the bottom of the case, it can also interfere with GPU fans if they're in close proximity.
Its not going to cause damage but it's not optimal at all.
If its a top mount psu case (which is an old standard nowadays and also not optimal compared to modern cases ) then it's fine, it will act an an extra exhaust for the CPU.
The psu WILL run hotter though.