EDIT: If it helps, here's a log of a session in which this issue occurred (abbreviated version with some bits removed for clarity):
2013-01-31 11:59:44 ----- OpenVPN Start -----
2013-01-31 11:59:44 LZO-ASYM init swap=0 asym=1
2013-01-31 11:59:44 Comp-stub init swap=0
2013-01-31 11:59:44 EVENT: RESOLVE
2013-01-31 11:59:44 EVENT: WAIT
2013-01-31 11:59:44 Connecting to 199.127.254.64:4398 (199.127.254.64) via UDPv4
2013-01-31 11:59:45 EVENT: CONNECTING
2013-01-31 11:59:45 Tunnel Options:V4,dev-type tun,link-mtu 1542,tun-mtu 1500,proto UDPv4,comp-lzo,keydir 1,cipher BF-CBC,auth SHA1,keysize 128,tls-auth,key-method 2,tls-client
2013-01-31 11:59:45 Peer Info:
IV_VER=1.0
IV_PLAT=ios
IV_NCP=1
IV_SNAPPY=1
IV_LZO=1
IV_LZO_SWAP=1
IV_COMP_STUB=1
2013-01-31 11:59:46 VERIFY OK: depth=0
...
2013-01-31 11:59:46 VERIFY OK: depth=1
...
2013-01-31 11:59:47 SSL Handshake: TLSv1.0/SSL-EDH-RSA-AES-256-SHA
2013-01-31 11:59:47 Session is ACTIVE
2013-01-31 11:59:48 EVENT: GET_CONFIG
2013-01-31 11:59:48 Sending PUSH_REQUEST to server...
2013-01-31 11:59:48 OPTIONS:
0 [redirect-gateway] [def1]
1 [ping-restart] [60]
2 [ping] [1]
3 [route-delay] [2]
4 [route-metric] [1]
5 [dhcp-option] [DNS] [98.158.112.60]
6 [dhcp-option] [DNS] [199.127.248.22]
7 [route] [10.8.1.249]
8 [topology] [net30]
9 [ifconfig] [10.8.1.254] [10.8.1.253]
2013-01-31 11:59:48 LZO-ASYM init swap=0 asym=1
2013-01-31 11:59:48 Comp-stub init swap=0
2013-01-31 11:59:48 EVENT: ASSIGN_IP
2013-01-31 11:59:48 Connected via tun
2013-01-31 11:59:48 EVENT: CONNECTED @199.127.254.64:4398 (199.127.254.64) via /UDPv4 on tun/10.8.1.254/
... NOTE: THIS IS ABOUT WHEN I STARTED TO ACCESS HTTP://WHATISMYIP.COM ... hangs for 40 seconds or so
2013-01-31 12:00:28 Session invalidated
2013-01-31 12:00:28 Client terminated, restarting in 2...
2013-01-31 12:00:30 EVENT: RECONNECTING
2013-01-31 12:00:30 LZO-ASYM init swap=0 asym=1
2013-01-31 12:00:30 Comp-stub init swap=0
2013-01-31 12:00:30 EVENT: RESOLVE
2013-01-31 12:00:30 EVENT: WAIT
2013-01-31 12:00:30 Connecting to 199.127.254.64:4398 (199.127.254.64) via UDPv4
2013-01-31 12:00:30 EVENT: CONNECTING
2013-01-31 12:00:30 Tunnel Options:V4,dev-type tun,link-mtu 1542,tun-mtu 1500,proto UDPv4,comp-lzo,keydir 1,cipher BF-CBC,auth SHA1,keysize 128,tls-auth,key-method 2,tls-client
2013-01-31 12:00:30 Peer Info:
IV_VER=1.0
IV_PLAT=ios
IV_NCP=1
IV_SNAPPY=1
IV_LZO=1
IV_LZO_SWAP=1
IV_COMP_STUB=1
2013-01-31 12:00:32 VERIFY OK: depth=0
...
2013-01-31 12:00:32 VERIFY OK: depth=1
...
2013-01-31 12:00:32 SSL Handshake: TLSv1.0/SSL-EDH-RSA-AES-256-SHA
2013-01-31 12:00:32 Session is ACTIVE
2013-01-31 12:00:33 EVENT: GET_CONFIG
2013-01-31 12:00:33 Sending PUSH_REQUEST to server...
2013-01-31 12:00:34 OPTIONS:
0 [redirect-gateway] [def1]
1 [ping-restart] [60]
2 [ping] [1]
3 [route-delay] [2]
4 [route-metric] [1]
5 [dhcp-option] [DNS] [98.158.112.60]
6 [dhcp-option] [DNS] [199.127.248.22]
7 [route] [10.8.1.249]
8 [topology] [net30]
9 [ifconfig] [10.8.1.254] [10.8.1.253]
2013-01-31 12:00:34 LZO-ASYM init swap=0 asym=1
2013-01-31 12:00:34 Comp-stub init swap=0
2013-01-31 12:00:34 EVENT: ASSIGN_IP
2013-01-31 12:00:34 Connected via tun
2013-01-31 12:00:34 EVENT: CONNECTED @199.127.254.64:4398 (199.127.254.64) via /UDPv4 on tun/10.8.1.254/
2013-01-31 12:00:53 EVENT: DISCONNECTED
2013-01-31 12:00:53 Raw stats on disconnect:
BYTES_IN : 12238
BYTES_OUT : 11773
PACKETS_IN : 116
PACKETS_OUT : 125
TUN_BYTES_IN : 2321
TUN_PACKETS_IN : 34
COMPRESS_ERROR : 44
KEEPALIVE_TIMEOUT : 1
N_RECONNECT : 1
2013-01-31 12:00:53 Performance stats on disconnect:
CPU usage (microseconds): 390427
Tunnel compression ratio (downlink): inf
Network bytes per CPU second: 61499
Tunnel bytes per CPU second: 5944
2013-01-31 12:00:53 ----- OpenVPN Stop -----