When both Detail Armor Bar and HWYLA Addon HorseInfo are loaded, the horse health bar renders incorrectly. This does not happen with only one of the two mods, and happens whether or not a version of WAILA/HWYLA/WTHIT is loaded.

This is in a fresh Minecraft instance and world:
Minecraft Log

I've cross reported this to Detail Armor Bar, and will delete the report here if it turns out your mod is not at fault.

Detail Armor Bar is at fault here. Closing the issue.