ConcurrentModificationException on SolrCore.close() resulting in abnormal CPU consumption

In our use case we swap two cores and close the old one. We started seeing the below error from time to time (it's completely random, we are unable to reproduce it). Moreover we have noticed that when this Exception is thrown the CPU consumption goes pretty high (80-100%).

Error Message:
java.util.ConcurrentModificationException: java.util.ConcurrentModificationException

StackTrace:
java.util.ArrayList$Itr.checkForComodification (ArrayList.java:901)
java.util.ArrayList$Itr.next (ArrayList.java:851)
org.apache.solr.core.SolrCore.close (SolrCore.java:1134)
org.apache.solr.servlet.HttpSolrCall.destroy (HttpSolrCall.java:513)
org.apache.solr.servlet.SolrDispatchFilter.doFilter (SolrDispatchFilter.java:242)
org.apache.solr.servlet.SolrDispatchFilter.doFilter (SolrDispatchFilter.java:184)
…ipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1668)
org.eclipse.jetty.servlet.ServletHandler.doHandle (ServletHandler.java:581)
org.eclipse.jetty.server.handler.ScopedHandler.handle (ScopedHandler.java:143)
org.eclipse.jetty.security.SecurityHandler.handle (SecurityHandler.java:548)
…g.eclipse.jetty.server.session.SessionHandler.doHandle (SessionHandler.java:226)
…g.eclipse.jetty.server.handler.ContextHandler.doHandle (ContextHandler.java:1160)
org.eclipse.jetty.servlet.ServletHandler.doScope (ServletHandler.java:511)
org.eclipse.jetty.server.session.SessionHandler.doScope (SessionHandler.java:185)
org.eclipse.jetty.server.handler.ContextHandler.doScope (ContextHandler.java:1092)
org.eclipse.jetty.server.handler.ScopedHandler.handle (ScopedHandler.java:141)
…e.jetty.server.handler.ContextHandlerCollection.handle (ContextHandlerCollection.java:213)
….eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:119)
org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:134)
org.eclipse.jetty.server.Server.handle (Server.java:518)
org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:308)
org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:244)
…pse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:273)
org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:95)
org.eclipse.jetty.io.SelectChannelEndPoint$2.run (SelectChannelEndPoint.java:93)
…il.thread.strategy.ExecuteProduceConsume.produceAndRun (ExecuteProduceConsume.java:246)
…e.jetty.util.thread.strategy.ExecuteProduceConsume.run (ExecuteProduceConsume.java:156)
org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:654)
org.eclipse.jetty.util.thread.QueuedThreadPool$3.run (QueuedThreadPool.java:572)
java.lang.Thread.run (Thread.java:745)