unable to download package of composite entity for import project

-It is working fine in PU 50(7.0.6354.76) and .Dll components is same 7.0.6354.76 with Custom entity and standard entity.

--It does not work in PU 50 below product build 7.0.6354.76 such that 7.0.6354.52 in Dev and higher in PU51 version on UAT instance, also no XML document is not visible in the folder on latest version and older version