funny grep behaviour, debian grep 2.12-2

Sorry, I had to edit lightly to remove some info.  But the gist remains - seems only the 2nd and later matches (or similar rule) in the file skip a line of context.

I note that the second alternative in the regex is the one that has its context properly reported ...   not sure if that is significant.

But, egrep worked properly.  Only grep shows this behaviour.



$ grep -n -A 2 'ClassID=\|provides' *.xml | grep -v -- '</' | less


Alias.xml:3:       provides="Alias">
Alias.xml-4-<!-- XXX  -->
Alias.xml-5-  <dataTypeDefs>
--
Alias.xml:27:    <ClassDef ClassID="114">
Alias.xml-29-      <synopsis>
--
AllTypes.xml:3:       provides="AllTypes">
AllTypes.xml-4-  <dataTypeDefs>
AllTypes.xml-5-     <dataTypeDef>
--
AllTypes.xml:102:    <ClassDef ClassID="116">
AllTypes.xml-104-      <synopsis>
--
AllTypes.xml:186:    <ClassDef ClassID="117">
AllTypes.xml-188-      <synopsis>
--