[luatex] No hyphenation when \lccodes zero with explicit hyphens

[Joseph Wright]

Hello all,

With minimal example

    \hsize=1.1cm %
    \noindent
    \hbox{}
    12-34-56

    \lccode`\2=`\2 %
    \lccode`\3=`\3 %
    \lccode`\4=`\4 %
    \noindent
    \hbox{}
    12-34-56
    \bye

LuaTeX as in TL2014 fails to break the first in the first paragraph but
does so in the second, whilst pdfTeX and XeTeX break both. Is this a
deliberate change of behaviour?
--
Joseph Wright