I cannot get prefix search to work on a scalar field. I can however get infix search to work which suggests that my field is not properly tokenized.

ENV: Standalone Milvus 2.4.8 on Ubuntu 22.04

Here is my schema:

{
fields: [
                {
                    name: 'id',
                    description: 'Id field',
                    data_type: DataType.VarChar,
                    is_primary_key: true,
                    max_length: this.NORMALISED_GUID_LENGTH
                },
                {
                    name: 'vector',
                    description: 'Vector field',
                    data_type: DataType.FloatVector,
                    dim: this.embeddingModel.dims
                },
                {
                    name: 'tag',
                    description: 'The partition tag',
                    data_type: DataType.VarChar,
                    max_length: this.NORMALISED_TAG_LENGTH
                },
                {
                    name: 'channels',
                    description: 'The channels that may access this entry',
                    data_type: DataType.VarChar,
                    max_length: this.MAX_CHANNELS_LENGTH
                },
                {
                    name: "payload",
                    description: 'The payload meta data',
                    data_type: DataType.JSON
                }
            ],
            partition_key_field: 'tag',
            index_params: [
                {
                    field_name: "vector",
                    index_type: "DISKANN",
                    metric_type: "IP"
                },
                {
                    field_name: "tag",
                    index_name: "tag_index",
                    index_type: "INVERTED"
                },
                {
                    field_name: "channels",
                    index_name: "channels_index",
                    index_type: "INVERTED"
                }
            ]
}

The field of interest is ‘channels’.

The channels field can look like this:
"48d302b1963841c39790fecf56b91ddc c8a80b710e455460ae8b2399f5adfef5 b9e8870f9f994bc6a172e118fa6e7c8a"

When I search it the filter looks like this (but it does not work):
'channels like "c8a80b710e455460ae8b2399f5adfef5%"' // note it is the 2nd token in the channels field above

The following infix search works:
'channels like "%c8a80b710e455460ae8b2399f5adfef5%"' // note it is the 2nd token in the channels field above

And the following prefix search works but only for the first token in the channels field:
'channels like "48d302b1963841c39790fecf56b91ddc%"' // note it is the 1st token in the channels field above

What am I doing wrong?