Retirement tax questions

Hi, 

What if I filed my form 8606 in 2020 but realized that the amount on line 2 was incorrect (accidentally left blank)? I corrected the prior balance in the 2021 return, but do I need to file an amended 8606 for 2020? 

There is currently an Explanation statement in the 2021 filing for my adjustment, but for some reason not for my spouses. Then, there is a blank form that explains both. Not sure how that happened.  What is the best way to fix this?

Thanks,

Marty