I was able to track down the problem: the paragraph in question included this sentence:
As there is a change of number; others will have ב, beth, or מ, mem, to be understood, They shall come with what they desire; that is, the nations shall not come empty, but shall gather all their treasures to be a holy oblation to God. (from the ccel.org site
Accordance was choking on ב and מ. Since the Hebrew letters remained Hebrew after I made the paragraph plain text in Text Edit, I presume the ccel site is using Unicode for Hebrew characters and words.
Is this a bug, or just a reality of Accordance's limited support for Unicode? Is it possible to at least have some sort of warning that explains why the paste doesn't work? Is there a workaround available?
Thanks and blessings,