CoreProtect seems to log the silverfish breaking the block (when leaving it), but the silverfish entering the block is not logged.
This may be logged with 2 entries : #silverfish breaking the stone block, then #silverfish placing the infested_stone block. The other blocks that can be infested should also be considered.

entity-change is enabled on my server.

In the following screenshot, I placed a stone block, and made a silverfish hide in this block (I spawned the silverfish next to it).
Then I spawned another silverfish and hit it, to make the other silverfish leave the stone block, breaking it at the same time.
CoreProtect logged me placing the stone block, and the silverfish breaking the infested_stone, but not the silverfish entering the stone block.