I should add, that further into this segment, N as a default is respected:
* Do you want to set PPAs for amd64 architecture (Y/n)?
Please enter 'Y' or 'N'!
* Do you want to set PPAs for amd64 architecture (Y/n)? y
* Do you want to set PPAs for i386 architecture (y/N)?
* Do you want to set PPAs for arm64 architecture (y/N)?
* Do you want to set PPAs for armhf architecture (y/N)?
* Do you want to set PPAs for ppc64el architecture (y/N)?
* Do you want to set PPAs for s390x architecture (y/N)?
*
* Adding PPAs for the following architectures: amd64
So the issue seems to be only when Y is the default.
I should add, that further into this segment, N as a default is respected:
* Do you want to set PPAs for amd64 architecture (Y/n)?
Please enter 'Y' or 'N'!
* Do you want to set PPAs for amd64 architecture (Y/n)? y
* Do you want to set PPAs for i386 architecture (y/N)?
* Do you want to set PPAs for arm64 architecture (y/N)?
* Do you want to set PPAs for armhf architecture (y/N)?
* Do you want to set PPAs for ppc64el architecture (y/N)?
* Do you want to set PPAs for s390x architecture (y/N)?
*
* Adding PPAs for the following architectures: amd64
So the issue seems to be only when Y is the default.