Flow action value of variable {{action.variableName}}

[hoang8829]

Flow Action often fails to set the value of the variable, the displayed variable value is action.variableName
Flow excute status is completed but when i check detail of value of step, the runtime value is {{action.variableName}}
When resetting the value of the variable (clear and reset to the same) the error is corrected and the flow runs normally.

But when updating (Upgrade instance, release new update Set ), the error repeats as above.
I try republish flow, but error is not resolved
I have followed clear snapshot instructions at Flow Designer Execution Error - (https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB0752296) but still error

Only when clearing the input value of the action and setting it again will the variable be set
But the error repeats again when there is a new update (Upgrade instance, release new update Set )

I would like to ask if anyone knows why the runtime value is not set?
And how to fix it so that the error does not happen again?
Thanks