To reproduce the issue:

• Create a sql table, the id is a LONG. insert a single value, id 1. 
• Configure the table jdbc store only and just map the value to protobuf. the key will be the long.
• From the rest api / console we will see that the key value are well mapped and the content type of the key is int64.
• Perfom a get key 1 where the protobuf type is a string (not a int64)

In readonly caches: the entry is found, and an additional entry will be created with key id 1 with content type string. So now we will have 2 entries in the cache. int64 1 and string 1. Try using double, or any other type that can be converted to 1. an additional entry will be added in the cache. The size of the cache grows.

In not read only caches, the entries are displayed in the entries rest api (5 entries with the same key 1 different content type in the key). however, the size of the cache returns 1 instead of the size we see in the rest api (5 for example)