– “The sotapanna has removed all vipallasa about anicca/nicca and anatta/atta. Thus, he/she does not make mistakes regarding the anicca and anatta nature”
I believe the interpretation of “Thus, he/she does not make mistakes regarding the anicca and anatta nature” could be of importance.
My interpretation of what was quoted would be sotapanna’s would know / have understood enough to be not induced / converted / conditioned to the wrong views / understanding of anicca/anatta. They would know / understand the general direction / idea / meaning of anicca/anatta. But to me, it doesn’t necessary mean what Sotapanna’s know or have understood about anicca/anatta “couldn’t be improved upon”.
– “Does it mean, the Sotapanna has full knowledge or panna about anicca/anatta?”
The key words are “has full knowledge”. Based on my current understanding and experience, I don’t believe Sotapanna’s have full knowledge or panna about anicca / anatta”. For me it’s hard to imagine that sotapanna’s understanding of the Tilakkhana and other teachings couldn’t be improved upon. It’s almost like saying, “once one is a Sotapanna, their understanding of anicca/anatta couldn’t be improved upon and that they would have complete knowing and understanding of it”.
I don’t think I could agree to such a statement.