in regards to Collatz conjecture when $3x + n$ and $n = 3^a$

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Starting any odd number $x$ with $3x + n$ and then dividing by $2$ until getting to the first odd, lets call it $y$.

For $3x + n$, when $n$ is not equal to $3^a$:

If $y$ ends in $1$ or $3$ or $7$ or $9$, it will have a sequence of $x$ made of numbers that end in a repeating pattern of 2 of the following: $1,3,5,7,9$ and every $y$ will have 2 of these patterns .

If $y$ ends in $5$ it will have an $x$ that has only 1 possible ending either: $1,3,5,7,9$

For example:

For $3x +1$ ($x$ on left $y$ on right):

___1,___5 → ___1

___7,___9 → ___1

___7,___9 → ___3

___5,___1 → ___3

___5 → ___3

___9,___7 → ___7

___1,___5 → ___7

___9,___7 → ___9

___5,___1 → ___9

For $3x + n$, when $n$ is equal to $3^a$:

If $y$ ends in $5$ it will have an $x$ that has only 1 possible ending either: $1,3,5,7,9$

If $y$ ends in $1$ or $3$ or $7$ or $9$, it will have one particular sequence made of all possible $1,3,5,7,9$ numbers expect if it is also the ending for $x$ if $y$ ends in $5$
(For every $n$ The order of the sequence is the same besides different beginnings)

For example:

For $3x +3$ ($x$ on left $y$ on right):

___3,___7,___5,___1 → ___1

___1,___3,___7,___5 → ___3

___9 ↦ ___5

___7,___5,___1,___3 → ___7

___5,___1,___3,___7 → ___9

When $n$ is not equal to $3^a$ the same pattern can lead to two different $y$, whereas when $n$ is equal to $3^a$ there is only one pattern for every possible $y$

Why is it happening? Can it be relevant to the conjecture? Any info about it will be appreciated.