Importing the same translation to a page modified in the default language second time generates empty warning

Steps to reproduce:

1. Create a space, activate Translations with two languages

2. Generate a translation ZIP

3. Modify the XML file and translate the content

4. Go to the same page in Confluence in default language → edit the content

5. Import the translation → A warning appears that "the following pages were modified in the default language..."

6. Click Close, Import the exact same translation XML

Expected result:

• Either no warning appears, or

• A warning should display the list of pages that were modified in the default language

Actual result:
An empty warning dialogue appears