4.7.5 Slate Brush Resource- Becomes null after 30 sec

[2015.04.16-18.35.36:899][531]LogReferenceChain: Generating reference chains …
[2015.04.16-18.35.36:900][531]LogReferenceChain:
[2015.04.16-18.35.36:900][531]LogReferenceChain: External Referencers:
[2015.04.16-18.35.36:901][531]LogReferenceChain:
[2015.04.16-18.35.36:902][531]LogReferenceChain: (root) (standalone) SlateBrushAsset /Game/UI/InGame/TeamInfos/NewSlateBrushAsset.NewSlateBrushAsset->ResourceObject
[2015.04.16-18.35.36:902][531]LogReferenceChain: MaterialInstanceDynamic /Game/Maps/Wip/UEDPIE_0_WipVM.WipVM:PersistentLevel.ZB4HUD_DOM_0.MaterialInstanceDynamic_30->Outer
[2015.04.16-18.35.36:903][531]LogReferenceChain: (PendingKill) ZB4HUD_DOM /Game/Maps/Wip/UEDPIE_0_WipVM.WipVM:PersistentLevel.ZB4HUD_DOM_0->Outer
[2015.04.16-18.35.36:904][531]LogReferenceChain: Level /Game/Maps/Wip/UEDPIE_0_WipVM.WipVM:PersistentLevel->OwningWorld
[2015.04.16-18.35.36:904][531]LogReferenceChain: (target) World /Game/Maps/Wip/UEDPIE_0_WipVM.WipVM
Fatal error: [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.7\Engine\Source\Developer\MessageLog\Private\Model\MessageLogListingModel.cpp] [Line: 70]
Critical Error ZB4PlayerState /Game/Maps/Wip/UEDPIE_0_WipVM.WipVM:PersistentLevel.MyPlayerState_1 Object from PIE level still referenced. Shortest path from root: (Object is not currently rooted)

UE4Editor.exe has triggered a breakpoint.