Possibly incorrect format in JMX cache stats

I posted a question on ML https://mail-archives.apache.org/mod_mbox/lucene-solr-user/201809.mbox/%3CCAGniRXR4Ps%3D03X0uiByCn5ecUT2VY4TLV4iNcxCde3dxBnmC-w%40mail.gmail.com%3E , but didn't get feedback. Since it looks like a possible bug, I am opening a ticket.

 
  It seems the format of cache mbeans changed with 7.4.0.  And from what I see similar change wasn't made for other mbeans, which may mean it was accidental and may be a bug.
 
  In Solr 7.3.* format was (each attribute on its own, numeric type):
 
mbean:
solr:dom1=core,dom2=gettingstarted,dom3=shard1,dom4=replica_n1,category=CACHE,scope=searcher,name=filterCache
 
attributes:
      lookups java.lang.Long = 0
      hits java.lang.Long = 0
      cumulative_evictions java.lang.Long = 0
      size java.lang.Long = 0
      hitratio java.lang.Float = 0.0
      evictions java.lang.Long = 0
      cumulative_lookups java.lang.Long = 0
      cumulative_hitratio java.lang.Float = 0.0
      warmupTime java.lang.Long = 0
      inserts java.lang.Long = 0
      cumulative_inserts java.lang.Long = 0
      cumulative_hits java.lang.Long = 0

 
  With 7.4.0 there is a single attribute "Value" (java.lang.Object):
 
mbean:
solr:dom1=core,dom2=gettingstarted,dom3=shard1,dom4=replica_n1,category=CACHE,scope=searcher,name=filterCache
 
attributes:
      Value java.lang.Object = {lookups=0, evictions=0, cumulative_inserts=0, cumulative_hits=0, hits=0, cumulative_evictions=0, size=0, hitratio=0.0, cumulative_lookups=0, cumulative_hitratio=0.0, warmupTime=0, inserts=0}