Tendermint version (use tendermint version or git rev-parse --verify HEAD if installed from source): 0.27.3-0138530d

ABCI app (name for built-in, URL for self-written if it's publicly available): kvstore

Environment:

• OS (e.g. from /etc/os-release): Ubuntu 17.04
• Install tools: all
• Others:

What happened:
'Added good transaction' is executed multiple times for same tx.
As I know, it means that one Tx is added so many times to mempool.

What you expected to happen:
One Tx is added to mempool only Once

Have you tried the latest version: yes

How to reproduce it (as minimally and precisely as possible):

Logs (paste a small part showing an error (< 10 lines) or link a pastebin, gist, etc. containing more of the log file):

The following is log for the Tx E9DBB1FB82...FD614756361B.
As you see, the tx is added to mempool so many times.

...
I[17126-12-17|15:24:44.453] Added good transaction module=mempool tx=E9DBB1FB82BD0E597F6138F7305376CA4192008262D6C83BFF8EFD614756361B res="&{CheckTx:gas_wanted:1 }" height=700 total=4304
I[17126-12-17|15:24:45.744] Could not check tx module=mempool tx=E9DBB1FB82BD0E597F6138F7305376CA4192008262D6C83BFF8EFD614756361B err="Tx already exists in cache"
I[17126-12-17|15:24:45.788] Could not check tx module=mempool tx=E9DBB1FB82BD0E597F6138F7305376CA4192008262D6C83BFF8EFD614756361B err="Tx already exists in cache"
I[17126-12-17|15:24:45.801] Added good transaction module=mempool tx=E9DBB1FB82BD0E597F6138F7305376CA4192008262D6C83BFF8EFD614756361B res="&{CheckTx:gas_wanted:1 }" height=701 total=267
I[17126-12-17|15:24:45.903] Could not check tx module=mempool tx=E9DBB1FB82BD0E597F6138F7305376CA4192008262D6C83BFF8EFD614756361B err="Tx already exists in cache"
I[17126-12-17|15:24:45.904] Added good transaction module=mempool tx=E9DBB1FB82BD0E597F6138F7305376CA4192008262D6C83BFF8EFD614756361B res="&{CheckTx:gas_wanted:1 }" height=701 total=459
I[17126-12-17|15:24:46.008] Could not check tx module=mempool tx=E9DBB1FB82BD0E597F6138F7305376CA4192008262D6C83BFF8EFD614756361B err="Tx already exists in cache"
I[17126-12-17|15:24:46.099] Added good transaction module=mempool tx=E9DBB1FB82BD0E597F6138F7305376CA4192008262D6C83BFF8EFD614756361B res="&{CheckTx:gas_wanted:1 }" height=701 total=802
I[17126-12-17|15:24:46.103] Could not check tx module=mempool tx=E9DBB1FB82BD0E597F6138F7305376CA4192008262D6C83BFF8EFD614756361B err="Tx already exists in cache"
I[17126-12-17|15:24:46.201] Could not check tx module=mempool tx=E9DBB1FB82BD0E597F6138F7305376CA4192008262D6C83BFF8EFD614756361B err="Tx already exists in cache"
I[17126-12-17|15:24:46.203] Could not check tx module=mempool tx=E9DBB1FB82BD0E597F6138F7305376CA4192008262D6C83BFF8EFD614756361B err="Tx already exists in cache"
I[17126-12-17|15:24:46.309] Could not check tx module=mempool tx=E9DBB1FB82BD0E597F6138F7305376CA4192008262D6C83BFF8EFD614756361B err="Tx already exists in cache"
I[17126-12-17|15:24:46.311] Added good transaction module=mempool tx=E9DBB1FB82BD0E597F6138F7305376CA4192008262D6C83BFF8EFD614756361B res="&{CheckTx:gas_wanted:1 }" height=701 total=1223
...

Config (you can paste only the changes you've made): Nothing

node command runtime flags:

/dump_consensus_state output for consensus bugs

Anything else we need to know:
I run 4 node and 2 validator node, in same network