Using commands like:
"/title @a title {text:"Chapter I", bold:true}"
issue a: "Invalid JSON format: Line 1 column 3 error.
I can't see you changing it so I thought I'd report it incase.
Linked issues
Comments 2

/title @a title {"text":"Chapter I", "bold":"true"} works.
You forgot to quote "true"
Duplicate of MC-83460 – If you searched the tracker before creating this report, and were unable to find the indicated ticket, please comment with the keywords you searched for so that the original report can be improved.