Cross coverage issue when using -master option while merging UCDBs


I am facing an issue when using the -master switch while merging UCDBs. I am using Questa64 10.2C

Let’s say the below are the cover group and cover points I have

[code]**module cvg_mc_fract_pel_h4
    input logic i_clk,
    input common_pkg::slice_ctrls  slice_ctrl_i,
    input common_pkg::ref_4pel_10bit_t ref_din_i,
    input common_pkg::ref_ctrls ref_din_ctrl_i

covergroup cg_mc_fract_pel_h4 @(posedge i_clk && ref_din_ctrl_i.vld);
  option.per_instance = 1;
  bit_depth: coverpoint slice_ctrl_i.bit_depth_8not10
	  bins bit8  = {1};
	  bins bit10 = {0};
  part_type: coverpoint ref_din_ctrl_i.part_type
	  bins pu_2Nx2N = {0};
          bins pu_2NxN  = {1};
	  bins pu_Nx2N  = {2};
	  bins pu_nxn   = {3};
	  bins pu_2NxnU = {4};
	  bins pu_2NxnD = {5};
	  bins pu_nLx2N = {6};
	  bins pu_nRx2N = {7};
  cross_parttype_bitdepth_bestvec : cross ref_din_ctrl_i.part_type, slice_ctrl_i.bit_depth_8not10;

In the above mentioned code if you see, cover point slice_ctrl_i.bit_depth_8not10 has 2 possible values, namely 0 and 1.

test1 would drive ‘1’ and hence only cover bin8 and test2 would drive ‘0’ and hence cover bin10. Individually when running these tests I see the coverages are fine.

Even when merging when I use the following, I dont see an issue…
cp …/tests/mc_frac_pel_h4/1/results/test-1.ucdb …/coverage/mc_fract_pel_h4/merge.ucdb
vcover merge -verbose -testassociated -out …/coverage/mc_fract_pel_h4/merge.ucdb …/tests/mc_frac_pel_h4/2/results/test-2.ucdb

By using the above mentioned I see the cross coverage happening properly and both bins of cover point slice_ctrl_i.bit_depth_8not10 get hit with all bins of cover point ref_din_ctrl_i.part_type

But when I use test-1.ucdb as “master”, the issue that I see is that cross between bin “bit8” of coverpoint slice_ctrl_i.bit_depth_8not10 is not shown merged with any of the bins of coverpoint ref_din_ctrl_i.part_type.
The commands I used for the above scenario is…
cp …/tests/mc_frac_pel_h4/1/results/test-1.ucdb …/coverage/mc_fract_pel_h4/merge.ucdb
vcover merge -verbose -testassociated -master …/coverage/mc_fract_pel_h4/merge.ucdb -out …/coverage/mc_fract_pel_h4/merge.ucdb …/tests/mc_frac_pel_h4/2/results/test-2.ucdb

I am not sure on what the “-master” switch might be doing to the cross coverage. Could you please help me out here.

Hope I was clear in the explanations. Let me know if anything else is needed.