[System Test] Indexing stuck, seeing multiple crashes on couch_set_view_updater.erl with badmatch error

Setup:

• 7 Nodes, 2 buckets, 1 ddoc,2 views
• 20 M items ( no DGM)
• rebalance in 1 node, with view-query 100 views/sec and 4-5k mix of upd-delete ops/sec across the cluster.
• Stop load, wait for indexing to complete

— Indexing keeps looping, making no progress beyond 2-3%.
— The couchdb log shows multiple crashes on couch_set_view/src/couch_set_view_updater.erl with a bad-match error.
"
error:

{badmatch,undefined}

stacktrace: [{couch_upr_client,enum_docs_since,8,
[

{file, "/buildbot/build_slave/centos-5-x64-300-builder/build/build/couchdb/src/couch_upr/src/couch_upr_client.erl"}

,

{line,166}

]},
{couch_set_view_updater,'load_changes/8-fun-2',12,
[

{file, "/buildbot/build_slave/centos-5-x64-300-builder/build/build/couchdb/src/couch_set_view/src/couch_set_view_updater.erl"},
{line,475}]},
{lists,foldl,3,[{file,"lists.erl"},{line,1248}]},
{couch_set_view_updater,load_changes,8,
[{file, "/buildbot/build_slave/centos-5-x64-300-builder/build/build/couchdb/src/couch_set_view/src/couch_set_view_updater.erl"}

,

{line,539}

]},
{couch_set_view_updater,'update/8-fun-2',14,
[

{file, "/buildbot/build_slave/centos-5-x64-300-builder/build/build/couchdb/src/couch_set_view/src/couch_set_view_updater.erl"}

,

{line,266}

]}]

[couchdb:error,2014-06-26T14:51:12.185,ns_1@10.6.2.163:<0.28486.6>:couch_log:error:42]Set view `saslbucket`, main (prod) group `_design/ddoc2`, received error from updater: {badmatch,
"

• The memcached log shows for the same vb-109(say) , it keep requesting for same seq nos
  Thu Jun 26 14:40:26.327523 PDT 3: (saslbucket) UPR (Producer) eq_uprq:mapreduce_view: saslbucket _design/ddoc2 (prod/main) - (vb 109) stream created with start seqno 30673 and end seqno 30721