Prefilling variables and then typing in the Html template does not work properly

[fayez-nazzal]

How to Reproduce

1. Open Fill Variables
2. type

{
  "test": "newvalue"
}

3. Save changes
4. in the Html template type: this is {{test}}

[fayez-nazzal]

Looks like typing it in the template overwrites it to:

{
  "test": ""
}