Taking a guess. If one of the lines is already on that layer then sometimes AC will not process the other ones. Try changing them to another layer first (hit ok) open Edit Selection again then change it to the one you want.
eduardo rolón AIA NCARB
Another of the forum moderators.
Macbook Pro M1 Max 64GB ram
OS X 10.XX latest
AC26 US/INT -> AC08
Puerto Rico, BVI, Miami
Vectorworks 2023