UGENE can't recognize VCF file produced by read-write workflow

Scenario to reproduce:

1. Create a workflow "Read variations -> Write variations".
2. Set "_common_data/snp/simple.snp" as input.
3. Set output document format to "vcf".
4. Launch workflow.
   Expected state: the workflow successfully finish, there is a new vcf file as a result.
5. Open the file in UGENE.
   Expected state: variation object is added to the project.
   Current state: the file is not recognized, user is offered to select file format. If select vcf, then the file opens.

Also, "Read variations" element can't read the result file.