How do we understand what is going on when the following error occurs in Cassandra?

[email protected]:$ nodetool compact
error: null
-- StackTrace --
java.lang.AssertionError
    at org.apache.cassandra.cache.ChunkCache$CachingRebufferer.<init>(ChunkCache.java:222)
    at org.apache.cassandra.cache.ChunkCache.wrap(ChunkCache.java:175)
    at org.apache.cassandra.io.util.FileHandle$Builder.maybeCached(FileHandle.java:412)
    at org.apache.cassandra.io.util.FileHandle$Builder.complete(FileHandle.java:381)
    at org.apache.cassandra.io.util.FileHandle$Builder.complete(FileHandle.java:331)