\font\foo="[lmroman10-regular]" at 10pt\foo
\TeXXeTstate=1\hsize=0pt
\hskip0pt Rindfleischetikettierungsüberwachungsaufgabenübertragungsgesetz
\vskip10pt
\hskip0pt\beginL Rindfleischetikettierungsüberwachungsaufgabenübertragungsgesetz\endL
\bye
If I remove the first line, the hyphenations is correct.
Anonymous
Yes, this appears to be a bug; thanks for reporting.
I think a workaround would be to add
\hskip0pt
before the\endL
command.Thanks for confirming, and for the nice workaround. Note that there was a problem with TeX--XeT and hyphenation before https://tex.stackexchange.com/questions/141769/bidi-and-hyperref-change-hyphenation, but now I guess this is related to how XeTeX shapes chunks of text (using ICU and HarfBuzz) when a system font is used (but I know nothing about the source code).