3       179230250       .       T       C       .       PASS    AC=1;AF=0.500;AN=2;AS_BaseQRankSum=0.062;AS_MQRankSum=-0.000;CONTQ=93;DP=20525;ECNT=2;GERMQ=93;LikelihoodRankSum=1.149;MBQ=20,20;MFRL=97,97;MMQ=60,60;MPOS=30;MQ0=0;MQRankSum=-0.000;NCount=0;POPAF=7.30;REF_BASES=TTTGGACACTTTTTGGATCAC;SEQQ=93;SOR=0.673;STRANDQ=29;Samples=240306_Tumor;TLOD=32.69;UNIQ_ALT_READ_COUNT=11 GT:AD:AF:DP:F1R2:F2R1:SB        0/1:20462,63:3.035e-03:20525:20434,63:0,0:10808,9654,33,30

7       55181378        .       C       T       .       strand_bias     AC=1;AF=0.500;AN=2;AS_BaseQRankSum=0.348;AS_MQRankSum=0.009;CONTQ=93;DP=24149;ECNT=5;GERMQ=93;LikelihoodRankSum=-8.168;MBQ=20,20;MFRL=125,125;MMQ=60,60;MPOS=26;MQ0=0;MQRankSum=0.009;NCount=0;POPAF=4.13;REF_BASES=CAGCTCATCACGCAGCTCATG;SEQQ=93;SOR=0.693;STRANDQ=1;Samples=240306_Tumor;TLOD=16.91;UNIQ_ALT_READ_COUNT=2  GT:AD:AF:DP:F1R2:F2R1:SB        0/1:24118,26:1.146e-03:24144:23963,26:0,0:12061,12057,13,13

variant1 and variant2 come from the same pipeline.

SB of variant1 is 10808,9654,33,30, and its SOR=0.673;STRANDQ=29. it "PASS" the filtering.

SB of variant2 is 12061,12057,13,13, and its SOR=0.693;STRANDQ=1. it failed to pass the filtering due to 'strand_bias'.

the 2 variants have similar SOR, but different STRANDQ. So I wonder how to caculate STRANDQ and why variant2 failed to pass the filtering?

Thanks!