_contained parameter seems to be ignored for cache hit purposes

[tadgh]

Search queries using _contained=truestore cached results

• Step 1: Enabled Indexing of contained resources
• Step 2: Created Contained resource
• Step 3: Query contained resource

http://localhost:8000/Observation?subject.name=Smith&_contained=true

Successfully found contained resource. Example - 1 result found.

• Step 4: Immediately Delete "_contained = True" from Query and run query again

http://localhost:8000/Observation?subject.name=Smith

Expected result : No Result Found
Actual Result : Result previous Search Query displayed.

• Step 5: after 5 min Run query again
  Actual Result : No result found.