Could a regulator creep in the heat and stay at a higher pressure?

I have, it still shoots low.
I just had the same thing happen to me a couple of days ago. My Taipan Vetran long was sighted in at 30 yards. I have all my dope written on a card. Mine was shooting 8 inches low at 81 yards. Shot at 50 and not as low but still low. I shot it a week or 2 earlier and my original dope card was right on. I didn't pull out my chronograph. But assumed it was shooting faster because of my past experience with reloading and shooting powder burner pistols. Faster shoots lower because the bullet exits the barrel faster with the recoil. I didn't think there was enough recoil on my 25 caliber to have that effect. I'm just going to play with it continually at different temperatures. I do know it's a tad slower in winter. Because I've chronographed it as I live in Michigan.