These two armour bars have a diamond helmet, leggings, and boots only. The leggings and boots both have Protection IV, and the helmet either has Blast Protection IV or Protection IV depending on which picture you're looking at. Not only does the animation go off the right of the armour bar (or show the enchantment on non-enchanted gear or empty slots if you have them on), but the Protection IV effects extends half an icon further than the Blast Protection IV one. Looking into it a bit more, it seems that Blast Protection IV always shows two full armour icons of animation, while Protection IV always shows two and a half, regardless of what armour piece it's on. It should really display the number of icons of animation corresponding to the armour points given by that piece of armour, instead of an arbitrary amount that doesn't change with what pieces of armour you have equipped and prevents you from filling the animation bar fully when not using Protection IV or that makes the animation overextend and look bad.

How far it extends depends on the level of the enchant as it seems.
But yea, agree, it doesn't look that good.