Exemgr crash on query happening when we increase 2 variables, MaxOutStandingRequests and RequestSize

Customer reported:

We are working on the latest 1.2-develop compiled version of columnstore. We have tested this issue with BOTH the gcc and Intel compiled versions. It appears there is a failure in ExeMgr and this causes the queries to fail, and in turn restarting ExeMgr as it should. This produces a corefile (21 G) and I will attach that output as well as the support report:

#0 0x000055e1a9f7cd35 in construct (this=0x7f955fbf5db0, __val=@0x7f986f800000: <error reading variable>, __p=0x7f958a037ef8) at /usr/include/c++/4.8.2/ext/new_allocator.h:130
#1 construct<unsigned int> (__a=..., __arg=@0x7f986f800000: <error reading variable>, __p=0x7f958a037ef8) at /usr/include/c++/4.8.2/ext/alloc_traits.h:216
#2 std::vector<unsigned int, std::allocator<unsigned int> >::_M_insert_aux (this=0x7f955fbf5db0, __position=<error reading variable: Cannot access memory at address 0x7f986f800000>, __x=<optimized out>) at /usr/include/c++/4.8.2/bits/vector.tcc:353

This appears to be happening when we increase 2 variables, MaxOutStandingRequests and RequestSize. This works with no errors: MaxOutStandingRequests = 60 RequestSize=2. However this causes the query failures and ExeMgr restart: MaxOutStandingRequests=120 RequestSize=2.