AC does not clean up the joints between slabs on floor plan (longstanding wish) so you are not doing anything wrong. The usual solutions/work arounds are to
• Turn the slab layer off for floor plans (recommended)
• Draw a white line or white fill over the joint
• Use GOs to override the uncut pen for those slabs (have not tried it)
AC floor plan views are not a projection.
You have found one of the annoying little items in AC for which all users have their workarounds.
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