This is an old bug report from 2009 that I stumbled upon while cleaning my mailbox:
http://www.mail-archive.com/lyx-users@lists.lyx.org/msg74832.html
It seems that the proposed fix never got applied: translate properly enumii/enumiii/enumiv in es.po.
After checking in babel sources which packages changes the enum* counters, I did the same thing to gl.po
#: lib/layouts/apa.layout:414 lib/layouts/apa.layout:415
#: lib/layouts/stdcounters.inc:48
msgid "(\\alph{enumii})"
-msgstr "(\\alph{enumii})"
+msgstr "\\alph{enumii})"
#: lib/layouts/armenian-article.layout:9
msgid "LatinOn"
#: lib/layouts/stdcounters.inc:53
msgid "\\roman{enumiii}."
-msgstr "\\roman{enumiii}."
+msgstr "\\arabic{enumiii})"
#: lib/layouts/stdcounters.inc:58
msgid "\\Alph{enumiv}."
-msgstr "\\Alph{enumiv}."
+msgstr "\\alph{enumiv}'"
#: lib/layouts/stdcounters.inc:68
msgid "Equation ##"
#: lib/layouts/apa.layout:414 lib/layouts/apa.layout:415
#: lib/layouts/stdcounters.inc:48
msgid "(\\alph{enumii})"
-msgstr "(\\alph{enumii})"
+msgstr "\\alph{enumii})"
#: lib/layouts/armenian-article.layout:9
msgid "LatinOn"
#: lib/layouts/stdcounters.inc:53
msgid "\\roman{enumiii}."
-msgstr "\\roman{enumiii}."
+msgstr "\\arabic{enumiii})"
#: lib/layouts/stdcounters.inc:58
msgid "\\Alph{enumiv}."
-msgstr "\\Alph{enumiv}."
+msgstr "\\alph{enumiv}'"
#: lib/layouts/stdcounters.inc:68
#, fuzzy