hitCount for referred items will not be increased while accessing parent item

While accessing an item, hitCount (in Dynamo component browser repository cache usage statistics) for referred items will not be increased.

For example - In PioneerCycling
In test4.jsp

<%@ taglib uri="dsp" prefix="dsp"%>
<dsp:page>
<dsp:importbean bean="/atg/commerce/catalog/ProductLookup"/>
<dsp:droplet name="ProductLookup" >
<dsp:param name="id" value="prod10023"/>
<dsp:param name="elementName" value="product"/>
<dsp:oparam name="output">
<dsp:valueof param="product.smallImage.url"/> <br>
</dsp:oparam>
</dsp:droplet>
</dsp:page>

By default PioneerCycling ProductCatalog has simple cache and item-cache-size for all items is 1000.
Before accessing this jsp

Product - accesscount is 0. Hit count is 0.
Media - accesscount is 0, hit count is 0.
Once test4.jsp is accessed for the first time.

Product - accesscount is 2, hit count is 0.
Media - accesscount is 6, hit count is 0.

First time access - In logs. select queries are fired.
[++SQLQuery++]
 SELECT t1.product_id,t1.version,t1.description,t1.nonreturnable,t1.brand,t1.end_date,t1.display_name,t1.disallow_recommend,
        t1.long_description,t1.creation_date,t1.start_date,t1.parent_cat_id,t1.product_type
   FROM dcs_product t1
  WHERE t1.product_id = ?
-- Parameters --
p[1] = {pd} prod10023 (java.lang.String)
[--SQLQuery--]
[++SQLSelect++]
 SELECT template_id,thumbnail_image_id,small_image_id,large_image_id
   FROM dcs_prd_media
  WHERE product_id=?
-- Parameters --
p[1] = {pd} prod10023 (java.lang.String)
[--SQLSelect--]

Once again if the test4.jsp is refreshed

Product - accessCount is 3, hit count is 1.
Media - accessCount is 6, hit count is 0.

As you can observe - neither the access count or hit count is increased for media items. But for product it got increased.
Note: Only first time queries are fired. Once items are cached there are no queries fired for product and media.
As test4.jsp is refreshed, product stats are getting increased but media stats are not getting increased.

Why?
Reason - (Below explanation is given by Oracle ATG support Nick Glover)
First time when product is accessed all its properties are loaded from database including media items, so for the first time accessCount for product and media items is increased. Once media items are loaded they are stored as references in the product property values. So, the next time the product is accessed, they don't need to be loaded at all, the product has a reference to them. This is not considered a cache hit on the media items because the media item cache is not being used in this situation; instead the product item cache is being used and its references to the media items are what is saving the trip to the database. And obviously, the hit ratio for media items is going to be 0% because the initial loading of them is a miss, and you have not done any direct requests for the media items that successfully found them in cache to get a cache hit.

Regarding Weak entry cache -
Suppose that number of products in application is 10000 and the item-cache-size is 5000
and number of media-items is 30000 (for each product 3 media-items) and the item-cache-size is 1000.
So if 1 product is accessed, 3 media items are loaded.

In above scenario, if 1000 products are accessed
product entry count is 1000 (in main cache)
media entry count is 1000 (in main cache)
media weak entry count is 2000 (in weak cache)

weak entry items in weak cache are not garbage collected until the referenced item (parent item) is removed/pushed from main cache.