Steps to reproduce:

1. Create new Content Type and add ezstring and ezlandingpage fieldtypes and set the alwaysAvailable flag to Not available.
2. Create fre-FR language.
3. Add fr site access with only language set to fre-FR.
4. Create Content from step 1) in eng-GB language and add any block to it.
5. Translate this content to fre-FR language.

Result:
The preview won't load. One will be presented with an exception that Location could not be loaded.

Expected result:
The preview should be loaded without any problems.