Thank you, that seems to allow CombineGVCFs to run.
gatk CombineGVCFs \
--java-options '-DGATK_STACKTRACE_ON_USER_EXCEPTION=true' \
-R "$GKREF"/Homo_sapiens_assembly38.fasta \
--variant "$OUT"/temp_gvcf_2/input.list \
-O "$OUT"/temp_gvcf_2/cohort.g.vcf
However, the resulting vcf file seems to only have one sample in it. The columns in the output are as follows:
#CHROM POS ID REF ALT QUAL FILTER INFO FORMAT M00819_262_000000000-BP6CG_1_
chr1 12046 . G <NON_REF> . . END=12410 GT:DP:GQ:MIN_DP:PL ./.:0:0:0:0,0,0
I'd expected a column of genotypes for each sample (i.e. 400 columns)??