Without knowing more about your data structure, what I imagine is happening is that the easements and parcels are being added to the fabric in the same parcel type.
Seeds get created when 3 criteria are met: parcel lines form enclosures; parcel lines belong to the same record; parcel lines are stored in the same parcel type.
Here is an example from testing:
1. The red lines represent a parcel. The purple lines represents an easement crossing the parcel. The lines for the parcel and the easement form enclosures, belong to the same record, but are stored in different parcel types:
2. Seeds are created for both parcels:
3. Build Active expands the seeds into parcel polygons according to their parcel types, while keeping them in the same record:
So the question becomes how to handle these situations when you're adding data to the fabric.
If you're using manual entry (aka the Traverse tool) you could create a traverse for the parcel lines, then a second traverse for the easements.
If you have the linework all ready to go (from a feature class), another strategy would be to create attribute fields that allow you to delineate the parcel lines from the easements: assign 0s and 1s to two attribute fields, one field that tells you whether a line is a parcel line; the second field to tell you whether a line is an easement.
After creating the attribute fields and assigning values to them, you can use Select By Attributes in combination with the Copy Lines To tool to generate seeds in the parcel type for parcels; then again to generate seeds for the easements parcel type.
Hopefully that helps!