gpg-agent crash with smartkey and enable-ssh-support

For unknown reason my gpg-agent crash frequently, I use it for enable-ssh-support in order to use ssh keys via smart keys Yubico

gpg2 --card-status

restart it without problem.

Is was working fine.

Could you give me hint to diagnose the problem, please?

lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.3 LTS
Release: 16.04
Codename: xenial

gpg-agent --version
gpg-agent (GnuPG) 2.1.11
libgcrypt 1.6.5

gpg2 --version
gpg (GnuPG) 2.1.11
libgcrypt 1.6.5
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Home: ~/.gnupg
Supported algorithms:
Pubkey: RSA, ELG, DSA, ECDH, ECDSA, EDDSA
Cipher: IDEA, 3DES, CAST5, BLOWFISH, AES, AES192, AES256, TWOFISH,
        CAMELLIA128, CAMELLIA192, CAMELLIA256
Hash: SHA1, RIPEMD160, SHA256, SHA384, SHA512, SHA224
Compression: Uncompressed, ZIP, ZLIB, BZIP2