negative value in `parameter_meta` parse error

[adthrasher]

For the following parameter_meta entry:

        alignSJstitchMismatchNmax: {
            description: "This overrides the STAR alignment default. Maximum number of mismatches for stitching of the splice junctions (-1: no limit) for: (1) non-canonical motifs, (2) GT/AG and CT/AC motif, (3) GC/AG and CT/GC motif, (4) AT/AC and GT/AT motif",
            tool: "star",
            tool_default: {
                noncanonical_motifs: 0,
                GT_AG_and_CT_AC_motif: -1,
                GC_AG_and_CT_GC_motif: 0,
                AT_AC_and_GT_AT_motif: 0
            }
        }

I am getting an unexpected parse error.

error: parse error
   ┌─ ./workflows/rnaseq/rnaseq-core.wdl:38:40
   │
38 │                 GT_AG_and_CT_AC_motif: -1,
   │                                        ^ The following tokens are required: metadata_value.

It is failing to parse the negative value. It works if I quote it / convert it to a string, but it should be acceptable as an integer.