Bottled LPG question

[wibwib74]

I currently have a manual changeover valve for 4 bottles in our house . 2 ran out this morning and I had to manually move the valve over then switch off the 2 empty ones and turned on the two full ones. When I did this I got a pop out of the main regulator somewhere, Is this right?? I am presuming due to the extremely warm weather we have been having the pressure has been a little high in the full tanks and the valve is just releasing the slight excess pressure?? Is this correct just startled me this morning when I did it at 5.30am after realising the shower was running cold. Any information would be appreciated