Apparently the paragraph formatter doesn't like 83-87 dashes being typed on the same line. The original bug report was filed in the Debian BTS at
There is some additional discussion there about where this might be caused - the joe wordwrap() function seems to be doing a double free(3), the backtrace says:
#5 0x0000000000457492 in joe_free (ptr=0xdb8b10) at utils.c:280
#6 0x0000000000446ef5 in wrapword (bw=0xdb88d0, p=0xdb5530, indent=88,
french=0, no_over=0, indents=0xdb8b10 '-' <repeats 87 times>, " ")
Alhough it's not immediately obvious to me when it would do that, or why different configuration settings would influence it (the Debian build crashes; the vanilla one doesn't).