Ошибка проверки SSL с помощью git (на github) в Ubuntu 14.04

Я пытаюсь клонировать репозиторий Atom, который только что стал полностью открытым и я столкнулся с некоторыми проблемами.

Пытаться git clone репозиторий выдает ошибку SSL:

wug@wugputer:/src/test$ git clone https://github.com/atom/atom.git
Cloning into atom...
error: SSL certificate problem, verify that the CA cert is OK. Details:
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed while accessing https://github.com/atom/atom.git/info/refs

fatal: HTTP request failed

Google указал, что это неудачный вызов CURL и что есть переменная среды, которую я могу установить для получения дополнительной информации, но она не показывает ничего особенно полезного:

wug@wugputer:/src/test$ GIT_CURL_VERBOSE=1 git clone https://github.com/atom/atom.git
Cloning into atom...
* Couldn't find host github.com in the .netrc file; using defaults
* About to connect() to proxy proxy.wugcorp.com port 3128 (#0)
*   Trying 10.1.2.3... * Connected to proxy.wugcorp.com (10.1.2.3) port 3128 (#0)
* Establish HTTP proxy tunnel to github.com:443
> CONNECT github.com:443 HTTP/1.1
Host: github.com:443
User-Agent: git/1.7.4.1
Proxy-Connection: Keep-Alive
Pragma: no-cache

< HTTP/1.0 200 Connection established
< 
* Proxy replied OK to CONNECT request
* Connected to proxy.wugcorp.com (10.1.2.3) port 3128 (#0)
* SSL certificate problem, verify that the CA cert is OK. Details:
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed
* Expire cleared
* Closing connection #0
* Couldn't find host github.com in the .netrc file; using defaults
* About to connect() to proxy proxy.wugcorp.com port 3128 (#0)
*   Trying 10.1.2.3... * Connected to proxy.wugcorp.com (10.1.2.3) port 3128 (#0)
* Establish HTTP proxy tunnel to github.com:443
> CONNECT github.com:443 HTTP/1.1
Host: github.com:443
User-Agent: git/1.7.4.1
Proxy-Connection: Keep-Alive
Pragma: no-cache

< HTTP/1.0 200 Connection established
< 
* Proxy replied OK to CONNECT request
* Connected to proxy.wugcorp.com (10.1.2.3) port 3128 (#0)
* SSL certificate problem, verify that the CA cert is OK. Details:
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed
* Expire cleared
* Closing connection #0
error: SSL certificate problem, verify that the CA cert is OK. Details:
error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed while accessing https://github.com/atom/atom.git/info/refs

fatal: HTTP request failed

Я на работе, proxy.wugcorp.com - это наш веб-прокси (он должен быть там). Я смог git клонировать вещи совсем недавно, на прошлой неделе, без каких-либо проблем. Я также могу curl файл git жалуется без всяких забавных трюков:

wug@wugputer:/src/test$ curl https://github.com/atom/atom.git/info/refs
Please upgrade your git client.
GitHub.com no longer supports git over dumb-http: https://github.com/blog/809-git-dumb-http-transport-to-be-turned-off-in-90-days

openssl также сообщает, что с сертификатом все в порядке:

wug@wugputer:/src/test$ openssl s_client -connect github.com:443 -CApath /etc/ssl/certs
CONNECTED(00000003)
depth=2 C = US, O = DigiCert Inc, OU = www.digicert.com, CN = DigiCert High Assurance EV Root CA
verify return:1
depth=1 C = US, O = DigiCert Inc, OU = www.digicert.com, CN = DigiCert SHA2 Extended Validation Server CA
verify return:1
depth=0 businessCategory = Private Organization, 1.3.6.1.4.1.311.60.2.1.3 = US, 1.3.6.1.4.1.311.60.2.1.2 = Delaware, serialNumber = 5157550, street = 548 4th Street, postalCode = 94107, C = US, ST = California, L = San Francisco, O = "GitHub, Inc.", CN = github.com
verify return:1
---
Certificate chain
 0 s:/businessCategory=Private Organization/1.3.6.1.4.1.311.60.2.1.3=US/1.3.6.1.4.1.311.60.2.1.2=Delaware/serialNumber=5157550/street=548 4th Street/postalCode=94107/C=US/ST=California/L=San Francisco/O=GitHub, Inc./CN=github.com
   i:/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert SHA2 Extended Validation Server CA
 1 s:/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert SHA2 Extended Validation Server CA
   i:/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert High Assurance EV Root CA
---
Server certificate
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
subject=/businessCategory=Private Organization/1.3.6.1.4.1.311.60.2.1.3=US/1.3.6.1.4.1.311.60.2.1.2=Delaware/serialNumber=5157550/street=548 4th Street/postalCode=94107/C=US/ST=California/L=San Francisco/O=GitHub, Inc./CN=github.com
issuer=/C=US/O=DigiCert Inc/OU=www.digicert.com/CN=DigiCert SHA2 Extended Validation Server CA
---
No client certificate CA names sent
---
SSL handshake has read 3233 bytes and written 443 bytes
---
New, TLSv1/SSLv3, Cipher is ECDHE-RSA-AES128-GCM-SHA256
Server public key is 2048 bit
Secure Renegotiation IS supported
Compression: NONE
Expansion: NONE
SSL-Session:
    Protocol  : TLSv1.2
    Cipher    : ECDHE-RSA-AES128-GCM-SHA256
    Session-ID: B5209FBCD0437CE4443399C5488071EAF6236ED8C489C0EF62E73A4453E3AB7C
    Session-ID-ctx: 
    Master-Key: 61E892AA74B881B7CE7C69DD0843B282BCAF6646282BB8099C2D3D84C63F3D311211822FB129432AE112A7E99BF07BCB
    Key-Arg   : None
    PSK identity: None
    PSK identity hint: None
    SRP username: None
    Start Time: 1399403523
    Timeout   : 300 (sec)
    Verify return code: 0 (ok)
---

Но самое странное, что оригинальный вызов git clone будет ВОСПРОИЗВОДИМО РАБОТАТЬ, если я запустил его в strace.

wug@wugputer:/src/test$ strace git clone https://github.com/atom/atom.git
[lots of output snipped]
[works correctly]

Понятия не имею, что происходит. Почему git так зол на сертификат github.com, когда все остальное с ним в порядке? и, что более важно, почему проблема исчезает, когда я пытаюсь ее проверить?