1.3.5. Avoiding Simulation Node Name Match
Node name mismatches happen when you have .vcd applied to entities other than the top-level entity. In a modular design flow, the gate-level simulation files created in different Intel® Quartus® Prime projects might not match their node names with the current Intel® Quartus® Prime project.
For example, you may have a file named 8b10b_enc.vcd, which the Intel® Quartus® Prime software generates in a separate project called 8b10b_enc while simulating the 8b10b encoder. If you import the .vcd into another project called Top, you might encounter name mismatches when applying the .vcd to the 8b10b_enc module in the Top project. This mismatch happens because the Intel® Quartus® Prime software might name all the combinational nodes in the 8b10b_enc.vcd differently than in the Top project.
You can avoid name mismatching with only RTL simulation data, in which register names do not change, or with an incremental compilation flow that preserves node names along with a gate-level simulation.