Dutch translation is not rendering ï and shows as question marks

Description

After installing the [Dutch language pack|
https://translations.atlassian.com/dashboard/download?lang=nl_NL#/Confluence/6.1.0] from translations.atlassian.com the character ï is translated as ? symbol.

Steps to reproduce

1. Install Dutch language pack to the confluence. Link: https://translations.atlassian.com/dashboard/download?lang=nl_NL#/Confluence/6.1.0
2. Click the {...}

   menu on a confluence page and you will notice the ï is translated as ? symbol.
   Ps: the character ï is render correctly when user insert the text in confluence page,

Expected Result
The character is translated correctly.

Actual result