Unable to restore Shelley pass phrase

Hi, Using Daedulus i transferred my Byron balance to the Shelley wallet (via the upgrade process in July/August 2020). I wrote down the 24 words and checked the wallet (i think i recall having to type the 24 seed words back in ???). I have tried to restore to another computer and the phrase is invalid. I have tried different combinations with no success.

Question 1 - is this a known issue ?

Question 2 - can i use daedulus offline to restore a pass phrase/wallet, the reason is i want to try alot of combinations but i am concerned about keyloggers and would prefer the extra security of being offline. Thanks, EC.