The chat window on PS4 appears to be ignoring the resolution-independent UI setting and always displaying at 120%.

Time: Irrelevant
Frequency: Irrelevant
World name: Irrelevant
Character name: Irrelevant
NPC name: Irrelevant
Monster name: Irrelevant
Class/Level: Irrelevant
Party or solo: Irrelevant
In-game time: Irrelevant
Area and coordinates: Irrelevant
Steps:
1. Open FF XIV
2. Log in & select a character
3. Press Options to display the main menu
4. Choose System -> System Configuration
5. Choose Display Settings
6. Change the default size from its current value (the default on PS4 is 120%, I chose 100%)
7. Press "Apply All"

Expected results:
When going from 120% to 100%, the UI is expected to shrink.

Actual results:
Everything shrinks _except_ for the chat window in the lower left corner, which stays the same. No matter what the default size is set to, the chat window never changes.

Model Number of the PlayStation®4 You Are Using
- Model Number: There's only one in North America