gas cap and cel(SES) code

tru_Asiatik

ok guys some back story when i first purchase the car and put gas on it after emptying the gas the dealership put(they put shell which i dont like)
my SES light came on after driving 70 miles
look at the manual and it mentioned could be a loose gas cap i didnt think nothing of it
disconnected the bat to reset the ses

now fast forward to when i got my hfc and exhaust installed went home put gas again the light came on again
so i had the guys from amplified check it this time
code for small evap leak P0456 showed
again futher reserch indicated could be a loose or bad gas cap
the ses was removed using a odb scanner this time
again i didnt think any of it

now 2000 miles later after putting gas again light came on
so now im taking it to the dealer

now to the question(i dont want to go uninformed when i face the dealer)

i was cleaning my car and cleaning the fuel tank i notice that it does not take any effort at all to twist the gas cap off i mean literally the slightest twist the gas cap comes off right away(no matter how many times i "Click" it when i close it)
it just comes off

is this normal??

thank you in advance

ps im aware of the TSB for this code so im printing it out as well

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