When using HUD type to hotbar. The chat screen is moved slighty upwards. so if there's hover event in chat, the hoverable location isn't moved upwards. Here's screen shots. I placed the mouse at the same location.

When HUD type is hotbar:

When HUD type is not hotbar:

to regenerate this, use this example command:
/tellraw @s {"text":"A text message","hoverEvent":{"action":"show_text","contents":[{"text":"hover text!"}]}}

• Edit: added screenshot with example command.

When HUD type is hotbar:

When HUD type is not hotbar:

Forge Version: 1.16.1-forge-32.0.98
Mod Version: [1.16.1][Forge] RPG-HUD-3.8.2