A note is marked twice by the note name plugin?

I looked at the OpenScore's Moonlight Sonata 1st Movement, measure 15, and it looks like screenshot 1 below.

And then when a custom note name plugin is applied, it looks like screenshot 2 below.

At first, I thought there is a bug in the plugin, but looking carefully, it appears somehow, the top B is show up twice: once as one beat, and once as part of the one beat (with two other notes).

Is it true it is not a bug of any kind, but it just means that, the first B note, is supposed to be held for the whole first beat, while the 3 other B notes later on in the measure, are supposed to be released right after the 1/3 beat is over?