The problem comes from a shared static instance of SchemaReader.
when readExternalPart is called, a boolean (deleteImports) determines if reader must use cached imported schemas or flush its cache before.
I do not understand how such a cache could be reliable. From a performance point of view, I cannot see any point either since imports should be resolved once at SA deployment time...
Otherly said, does anybody know why this cache was originally introduced ??
If no proper reason is given, a possible fix is to never use the cache.
It seems like the svn.zip does not contain all the required XSDs. I have put them in the blocked issue