Issue with terraform integration

hello, we followed this document in order to make integration with terraform: Terraform integration in Merge Requests | GitLab

our gitlab is 13.6.1-ce.0.el7 version

however in MR widget there is not information about terraform plan, however the json file with plan was created (plan.json)

also, we use registry.gitlab.com/gitlab-org/terraform-images/releases/0.12 for teraform gitlab integration