Error CMP501: The nets <your net1> and <your net2> are sharing <instance> instance(s) which are assigned to disjoint local clock regions
Inserted <bfr> buffer(s) on the net <your net3> for legalization.

Two nets cannot be assigned to non-overlapping local clock regions if they share instances. The Compile command automatically inserts buffers on one of the two nets to remove the shared instance constraint and guarantee that the two nets can be assigned to the specified local clock regions

Action

• Verify that the automatic buffer insertion is acceptable for this design.

• If the automatic insertion of buffer is not acceptable, consider assigning the two nets to overlapping local clock regions. Make sure that the LocalClock regions are big enough to contain the macros driven by these nets.