A number of overlapping issues with the Enhanced Boss Bars texture pack, Jade HUD and Xaero's map icons. Custom boss bar textures display inside the Jade HUD - as well as the fact that I have "display bosses" turned off yet the HUD still shows and overlaps with the actual boss bar. Boss bar textures are also displayed as if icons on Xaero's Minimap & Worldmap. Without the Enhanced Boss Bars texture pack there is still the issue with the Jade HUD overlapping.

Can you send a screenshot please?

This seems like an issue with Enhanced Boss Bars texture pack, Jade HUD and Xaero's map.
I tried turning off custom boss bars in the Mowzie's Mobs client config and it worked fine.