Thanks for picking this up. I've passed this information on to the guy who's in charge of this module, and hopefully he can fix it.
I'm not sure what you're displaying in the screenshot, but looking at Matthew 2:2, I see:

$$$Matthew 2:2
「ユダヤ人の<lb type="x-end-paragraph"/> <lb type="x-begin-paragraph"/>王<lb type="x-end-paragraph"/> <lb type="x-begin-paragraph"/>としてお生まれになった方はどこにおられますか。わたしたちは東方でその方の星を見たので，その方を拝むために来たのです」。

Which shows an error in the markup of the text. I'm not sure why there are extra paragraph markers around certain words, but that's why it's displaying in a rather frustrating way.

I have checked the website that publish Denmo Japanese Version.

It says GBF is used for their master data.
There comes Mat3:2 ..
<SV2>「悔い改めなさい。<FU>天<Fu>の<FU>王国<Fu>は近づいたからだ！」　

According to the site, <FU> means underlined.

So, I guess every <FU> is mistakely interpreted when converting to OSIS.

by the way, GBF is not a subset of XML.
It does not close every opened tags. It's more like HTML.
I guess the conversion was a bit of headache...

As I said before, this translation is not completed, unpopular, very minor and not updated since 2002.

Sadly, all "modern Japanese" Bibles are copyrighted, there is none like World English Bible.
So, the presence of this version might stir up others to work on something like WEB.

This is an odd bug. I checked, and the GBF to OSIS converter is generating <p>...</p> for <FU>...<Fu>. What is odd is that this converter was written by the guy who wrote the GBF specification. He must not ever use <FU> in the WEB.

I can try to do the job... But the link to gbf2osis.pl is dead. And adyeth is bugged.

I did an new osis file, I will send you the link soon. After new release this issue can be closed.