Imagine, a 'new' oldfrisian text is discovered and proven to be authentic.
It is a few hundred pages long, and older than any known oldfrisian text.
Would it be intelligent to expect and demand that it only has words in it that are already known from the texts we have and in the exact same meaning that we know them?
Wouldn't it be very possible that we would discover that some words and expressions are actually older than we thought?
In some of the many fragments I could have used from the OLB 'estate' could be a possible translation, but in some of the ones I posted 'nation' is the only logical option.
The problem with 'modern' words showing up in a manuscript that is supposed to be millennia old, is that in much more recent manuscripts these words are never used in that meaning.
Like: 3000 years ago XXX meant 1234, then 2000 years later XXX meant 4567, and then again just a few centuries ago it suddenly meant 1234 again.
That is not very likely to happen.