Hello,
it could be the application issue or LCAPPS, or liveCache < see SAP note 2068007 & search "oms heap" > issue.
Information on the application scenario, data selection, SCM system version SP, the LCAPPS and liveCache version including the build, memory availability on the liveCache server & current OmsMaxHeapSize and oms_heap_count values will be helpful to check first.
I recommend you to create the SAP message to the component BC-DB-LVC or BC-DB-LCA and get SAP support.
Regards, Natalia Khlopina