Creating grafana alert using terraform getting error failed to parse expression 'C': threshold expression requires exactly one condition

[CAEXT154]

Hello team,

I am encountering an issue while creating a Grafana alert using Terraform. The error message is:
"failed to parse expression 'C': threshold expression requires exactly one condition".

However, when I copy the same query and use it in Grafana's Explore section, it works as expected. Additionally, exporting the alert configuration and creating it manually also works without any issues. This problem seems to occur only when provisioning the alert via Terraform.

Below is the relevant Terraform code block:

content {
      name           = "${rule.value.env}_${rule.value.name_suffix}_${rule.key}"
      condition      = "C"
      no_data_state  = "OK"
      exec_err_state = "Error"
      annotations = {
        summary     = replace("${rule.value.name_suffix} ({{severity}})", "{{severity}}", rule.value.severity)
        description = replace(replace(rule.value.description, "{{threshold}}", rule.value.threshold), "{{duration}}", rule.value.duration)
        threshold   = rule.value.threshold
        duration    = rule.value.duration
      }
      labels = {
        combined_label = "${var.team_name}-${var.product}-${each.key}-${var.random_suffix}"
      }
      # Block A: Query (full-form model)
      data {
        ref_id = "A"
        relative_time_range {
          from = 600
          to   = 0
        }
        datasource_uid = var.datasource_uid
        model = jsonencode({
          editorMode = "builder"
          exemplar   = false
          expr = replace(
            replace(
              rule.value.expr_template,
              "{{labels}}",
              join(",", [for k, v in rule.value.labels : "${k}=\"${v}\""])
            ),
            "{{duration}}",
            rule.value.duration
          )
          format        = "table"
          instant       = false
          intervalMs    = 1000
          legendFormat  = "__auto"
          maxDataPoints = 43200
          range         = true
          refId         = "A"
        })
      }
      # Block B: Reduce
      data {
        ref_id = "B"
        relative_time_range {
          from = 0
          to   = 0
        }
        datasource_uid = "__expr__"
        model = jsonencode({
          datasource = {
            name = "Expression"
            type = "__expr__"
            uid  = "__expr__"
          }
          expression    = "A"
          intervalMs    = 1000
          maxDataPoints = 43200
          reducer       = "last"
          refId         = "B"
          type          = "reduce"
        })
      }
      # Block C: Threshold
      data {
        ref_id = "C"
        relative_time_range {
          from = 0
          to   = 0
        }
        datasource_uid = "__expr__"
        model = jsonencode({
          datasource = {
            type = "__expr__"
            uid  = "__expr__"
          }
          expression    = "B"
          intervalMs    = 1000
          maxDataPoints = 43200
          threshold     = rule.value.threshold
          operator      = rule.value.operator
          refId         = "C"
          type          = "threshold"
        })
      }
      is_paused = false
      notification_settings {
        contact_point   = "email-devops"
        group_by        = null
        group_wait      = "30s"
        group_interval  = "5m"
        repeat_interval = "1m"
      }
    }

```

[CAEXT154]

@julienduchesne @spinillos @trotttrotttrott @inkel @inkel @alexweav @jonathan-dorsey
could you please help on this :)