snpeff effect annotation confusion

[najoshi]

So I am trying to figure out why this particular complex variant was annotated with an effect of "start_lost" when I don't see any evidence of the start codon being changed. Here is the full vcf line:

chr1	20717668	.	ACGGCAGCGCACGACAACCTTCACCGCCTCGGAGGCCATGGCGCCGCGCCCAGGACCAA	GCGGCAGCGCACGACAACCTTCACCGCCTCGGAGGCCATGGCGCCGCGCCCAGGACCAC	566.598	.	AB=0.347826;ABP=12.2627;AC=5;AF=0.5;AN=10;AO=16;CIGAR=1X57M1X;DP=46;DPB=46.1525;DPRA=0;EPP=5.18177;EPPR=4.16842;GTI=0;LEN=59;MEANALT=1;MQM=60;MQMR=60;NS=5;NUMALT=1;ODDS=5.38955;PAIRED=0.5625;PAIREDR=0.466667;PAO=9;PQA=333;PQR=0;PRO=0;QA=586;QR=1103;RO=30;RPL=13;RPP=16.582;RPPR=31.9633;RPR=3;RUN=1;SAF=7;SAP=3.55317;SAR=9;SRF=8;SRP=17.1973;SRR=22;TYPE=complex;ANN=GCGGCAGCGCACGACAACCTTCACCGCCTCGGAGGCCATGGCGCCGCGCCCAGGACCAC|start_lost|HIGH|KIF17|KIF17|transcript|NM_020816.4|protein_coding|1/15|c.-20_39delTTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGTinsGTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGC|p.MetAlaSerGluAlaValLysValValValArgCysArg1?|340/3961|1/3090|1/1029||,GCGGCAGCGCACGACAACCTTCACCGCCTCGGAGGCCATGGCGCCGCGCCCAGGACCAC|start_lost|HIGH|KIF17|KIF17|transcript|NM_001122819.3|protein_coding|1/15|c.-20_39delTTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGTinsGTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGC|p.MetAlaSerGluAlaValLysValValValArgCysArg1?|340/3958|1/3087|1/1028||,GCGGCAGCGCACGACAACCTTCACCGCCTCGGAGGCCATGGCGCCGCGCCCAGGACCAC|5_prime_UTR_variant|MODIFIER|KIF17|KIF17|transcript|NM_020816.4|protein_coding|1/15|c.-20_39delTTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGTinsGTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGC||||||,GCGGCAGCGCACGACAACCTTCACCGCCTCGGAGGCCATGGCGCCGCGCCCAGGACCAC|5_prime_UTR_variant|MODIFIER|KIF17|KIF17|transcript|NM_001122819.3|protein_coding|1/15|c.-20_39delTTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGTinsGTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGC||||||,GCGGCAGCGCACGACAACCTTCACCGCCTCGGAGGCCATGGCGCCGCGCCCAGGACCAC|5_prime_UTR_variant|MODIFIER|KIF17|KIF17|transcript|NM_001287212.2|protein_coding|1/15|c.-447_-389delTTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGTinsGTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGC|||||2098|,GCGGCAGCGCACGACAACCTTCACCGCCTCGGAGGCCATGGCGCCGCGCCCAGGACCAC|downstream_gene_variant|MODIFIER|SH2D5|SH2D5|transcript|NM_001103161.2|protein_coding||c.*4066_*4124delTTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGTinsGTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGC|||||2063|,GCGGCAGCGCACGACAACCTTCACCGCCTCGGAGGCCATGGCGCCGCGCCCAGGACCAC|downstream_gene_variant|MODIFIER|SH2D5|SH2D5|transcript|XM_011541459.2|protein_coding||c.*4066_*4124delTTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGTinsGTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGC|||||2063|,GCGGCAGCGCACGACAACCTTCACCGCCTCGGAGGCCATGGCGCCGCGCCCAGGACCAC|downstream_gene_variant|MODIFIER|SH2D5|SH2D5|transcript|XM_011541460.2|protein_coding||c.*4066_*4124delTTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGTinsGTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGC|||||2063|,GCGGCAGCGCACGACAACCTTCACCGCCTCGGAGGCCATGGCGCCGCGCCCAGGACCAC|downstream_gene_variant|MODIFIER|SH2D5|SH2D5|transcript|XM_011541462.2|protein_coding||c.*4066_*4124delTTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGTinsGTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGC|||||2063|,GCGGCAGCGCACGACAACCTTCACCGCCTCGGAGGCCATGGCGCCGCGCCCAGGACCAC|downstream_gene_variant|MODIFIER|SH2D5|SH2D5|transcript|XM_011541461.2|protein_coding||c.*4066_*4124delTTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGTinsGTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGC|||||2063|,GCGGCAGCGCACGACAACCTTCACCGCCTCGGAGGCCATGGCGCCGCGCCCAGGACCAC|downstream_gene_variant|MODIFIER|SH2D5|SH2D5|transcript|NM_001103160.2|protein_coding||c.*4066_*4124delTTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGTinsGTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGC|||||2063|,GCGGCAGCGCACGACAACCTTCACCGCCTCGGAGGCCATGGCGCCGCGCCCAGGACCAC|intron_variant|MODIFIER|LOC107985528|LOC107985528|transcript|unknown_transcript_1|protein_coding|987/1510|c.167449+904178_167449+904236delTTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGTinsGTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGC||||||WARNING_TRANSCRIPT_MULTIPLE_STOP_CODONS;LOF=(KIF17|KIF17|3|0.67)	GT:DP:AD:RO:QR:AO:QA:GL	0/1:4:3,1:3:111:1:37:-2.49371,0,-9.14896	0/1:9:6,3:6:221:3:109:-13.5154,0,-16.9355	0/1:11:6,5:6:223:5:182:-16.4518,0,-16.8162	0/1:12:8,4:8:294:4:149:-22.2684,0,-21.995	0/1:10:7,3:7:254:3:109:-13.2144,0,-19.5986

The first annotation looks like this:

GCGGCAGCGCACGACAACCTTCACCGCCTCGGAGGCCATGGCGCCGCGCCCAGGACCAC|start_lost|HIGH|KIF17|KIF17|transcript|NM_020816.4|protein_coding|1/15|c.-20_39delTTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGTinsGTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGC|p.MetAlaSerGluAlaValLysValValValArgCysArg1?|340/3961|1/3090|1/1029||

For some reason it is calling it a deletion & insertion instead of just two separate SNPs. Looking at the two sequences:

TTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGT
GTGGTCCTGGGCGCGGCGCCATGGCCTCCGAGGCGGTGAAGGTTGTCGTGCGCTGCCGC

you can see that all of the bases are the same except for the first and last bases. The start codon is in the middle, i.e. this variant crosses the 5'UTR to exon 1 boundary. However, the start codon does not change, so why is it being annotated as a "start_lost"?