Wiki is failing when using data from issue used in a previous level mappings

Description

Wiki Markup fails whenever there is an issue used before for some previous level mapping.

How to reproduce

1. Install the template "wiki on execution defects"
2. Create a test plan
3. Create a test "aaa"
4. Create a test run
5. Add the test "aaa" as execution defect
6. Export the test plan using the template installed in the step 1

Actual result/Attachments

Basically since the test is used in a previous mapping

${Overall Execution Status.TO DO.Percentage}

This test is saved in cache without renderedFields. Since there is not rendered fields, the template throws an error.

Expected result

As a result the template should export correctly, generating a document with the correct test description in wiki.