After updating my Confluence to version 7.4.0, most of my graphs and diagrams on dashboard started showing garbled text on labels and captions. Every other text was okay.
This is most probably due to the missing fonts in your Linux installation.
This article on Attlassian site has the answer. My Linux is already patched with the latest official updates.
OS: Centos 7.4.1708
Confluence Server: v6.5.0
To fix it you need to install the missing fonts.
sudo yum install ghostscript \ dejavu-fonts-common \ dejavu-sans-fonts \ dejavu-sans-mono-fonts \ motif
In order for Confluence to pick up the changes, apply the below steps:
sudo systemctl stop confluence
Rebuild the font cache by using the following command:
sudo fc-cache -s
sudo systemctl start confluence
Clear your browser cache and verify Confluence is presenting the text properly.