A320 refuel panel switch left in refuel position
 

Are there any fuel system problems likely to occur in flight or on ground after aircraft lands, if "Refuel/off/Defuel" switch left in "Refuel" position after refuel operation is over?
Refuel buses 501PP and 502 PP are not powered in flight,so fuel system operation may not be affected, but procedure insists on returning the switch to "off" position after refuel operation and it is a normal practice always.

My refuelling panel "automatically" closes all refuelling switches. Doesn't yours?

Refueling valves are not opened electrically - they are allowed to open with refueling pressure from the refuelling truck so there will be no adverse effect if the switch is left on.Most refueling systems are unpowered in flight in any case.

No. Our A320 have the refuel panel mounted in the wing/body fairing, like every other A320 I have seen. (Are there any with wing mounted panels? I have seen it is an option but never seen one)
Closing the refuel panel door does not close the switches, it operates a microswitch that removes power from the refuel system.
The reason to return the switches to off is not to cause trouble on the next refuelling.

Steve,
Thread drifting here but we had an A320 on lease to us through the summer with the refuel panel mounted on the left wing. First one in 20+ years I'd ever seen. Still has a refuel coupling on both sides, refuel ops exactly the same as wing/body mounted panel. The only issue was when the aircraft was parked on a stand with a refuel pit on the right side only, then you had to remember to take some steps with you.

Thanks for all for inputs, these are some of my doubts after going through manuals,
The "Refuel" switch position input is directly connected to the FQI Computer,
the FQI computer supposed to close intercell transfer valves at beginning of refueling (if they are open in flight that just concluded).
Intercell transfer valves control logic is probably controlled by software inside FQI,
when refuel switch is returned to "off" it may be enabling the control logic to open in flight when low quantity sensed in inner cell. So if you do not return the switch to "off",it may affect this operation.
Any time new fuel is added to tanks,the FQI calculates new density and capacitive index for accurate fuel quantity indication,if the switch is left in "Refuel" it may affect this calculation inside computer.
Now a days many functions are done by software inside the computer based on certain algorithms and hardware inputs, so it is difficult to come to any valid conclusion unless it is given in the manual.