Umarex Windage adjustment day to day ?

I'm a little confused as to why I might have to adjust my left/right windage on the scope daily.
Notos with Hatsan 3x9 x 40 scope. Zeroed at power 5X ( as I like to shoot on 5). All screws are tight / no movement on scope.
as an example:
Day One: zeroed it in & shooting with amazing acuaracy at 25 yards. Stored my Notos safetly & securely. No dropping or carrying by the scope etc..
Day Two: Took the first 4 shots and it layed out a cluster no bigger than a dime however, it was about 3/4" to the left. Figuring the Notos is acuarte I adjusted the scope about 12 clicks to the right & it was spot on for the next 30 - 40 shots. Then I stored the gun again.
Day Three: first three shots are 1/2" - 3/4" to the right this time ??? .... 12 clicks to move it back to the left & spot on for the rest of the session. This time I Zeroed it a full 9X power. Then backed it off to the lowest 3x's and untilmatly 5X which all powers were spot on. Took about 40 shots , left it on 5X's & stored it.
A few days later (Yesterday): Same thing ?? 1/2" to the left. corrected it & spot on.

Is it possible that coming from a very cool 70* of air conditioning to 84* of So. Florida heat can move the components ? throwing off the scope ?
If this is common ( I don't think it is), I can live with a correction on the first few shots of each session.
 
Do the following:

1.- Hit gently the scope aside of the rifle with a rubber hammer. Below the turrets and over the torrents. Gently !!

2.- Take the caps of the turrets out and then first give all clicks to left, then to right and take it back to center. Then do the same with up and down turret: all clicks down, then left and go back to center.

3.- Let the scope rest for an hour.

4.- Re-zero your scope at desire distance.

You will have a very slow variation from the re-zero to the next shooting session and thereafter no variation at all.
 
I took some time this week to experiment on my Notos in thinking about this phenomenon. With a non modded gun and a 3x12 bugbuster scope, I couldn't move the poi with scope or barrel bumps. I did have 1 first shot go an inch to the left but that could have been a flier as it was not present on the second shot.

I do know that the plastic picrail is prone to being over tightened and lossening up (a gun I worked on last night had the screws down so far the picrail was distorted) if you don't follow the guidelines for scope ring tightening.

15-18 inch pounds is all you need for rings and 25 inch pounds for bases. Read your installation instructions for your torque.