Entity Framework 5 on framework 4, contains and multiple outer joins with same table -

i having strange issue on application when deploying on windows 2008 r2 server.

given simple linq snippet:

return     invoice in me.invoices     loggedcustomerid.contains(invoice.contract.customerid) order     invoice.date descending 

the application works, in some cases (on customer server), generated t-sql strange:

 select      [extent1].[contractid] [contractid], ...      [dbo].[invoice] [extent1]     inner join [dbo].[contract] [extent2] on               [extent1].[contractid] = [extent2].[contractid]     left outer join [dbo].[contract] [extent3] on               [extent1].[contractid] = [extent3].[contractid]          [extent2].[customerid] = 482283     or [extent3].[customerid] in (498565,482282,498564,498566) 

• table linked multiple times (?)
• the in statement broken multiple t-sql conditions instead of single in statement

obviously same package runs fine on system generating correct query without linking same table multiple times , creating single in statement.

i using ef 5.0 compatibility against framework 4.0 (so assembly shows version 4.4). root cause of issue?

what wrong here?

it looks behavior related this? too many left outer joins in entity framework 4?

i've met analogous behavior in nhibernate, maybe find similarity.

we got simple parent -> children relation. point relation bidirectional parent referenced children , each of them has reference parent.

nhibernate supports lazy fetching switch off. produced interesting query once decided fetch whole aggregate, mean parent children.

something like:

select ... parent ... left join ... children ... left join parent

as nhibernate uses first level cache under hood, not able discover automatically parent instances equal cache of parent empty in time of query execution.

later during parsing of resulting database dataset, nhibernate found out parent entities have same primary identifier , returned 1 real instance.