Game and Plater version
Which is the game version and Plater version you're using?
Plater-v598-Vanilla - DF v586 - 1.15.5

Describe the bug
The nameplate is not lined up, like it looks disconnected. See screenshot.

Lua Error

Screenshots

Other Information
If necessary, add more info here.

I have no idea what you mean. This looks perfectly normal.

I don't know if this is intentional, but it seems like the two end points are offset or not the same width as the center piece.

I don't think they are. Check on full health units. And if they are, it is likely due to pixel perfect shenanigans caused by UI scale and similar settings...