Adding my experience. It seems to happen to me every night around 7:30 or 8 PM CST and lasts for an hour or longer. I can clear it up immediately by turning my VPN on, but I shouldn't have to rely on that.

Code:
Tracing route to 204.2.229.105 over a maximum of 30 hops

  1    <1 ms    <1 ms    <1 ms  dsldevice.attlocal.net [192.168.1.254]
  2     1 ms     1 ms     1 ms  45-20-24-1.lightspeed.hstntx.sbcglobal.net [45.20.24.1]
  3     1 ms     1 ms     1 ms  71.149.39.122
  4     *        *        *     Request timed out.
  5     *        *        *     Request timed out.
  6     *        *        *     Request timed out.
  7    12 ms    12 ms     7 ms  32.130.16.9
  8    10 ms    11 ms    12 ms  gar25.dlstx.ip.att.net [12.122.85.233]
  9     *       71 ms    58 ms  ae-5.a00.dllstx14.us.bb.gin.ntt.net [129.250.8.237]
 10     *       65 ms    80 ms  ae-2.r21.dllstx14.us.bb.gin.ntt.net [129.250.4.19]
 11    44 ms    46 ms    45 ms  ae-2.r25.snjsca04.us.bb.gin.ntt.net [129.250.4.154]
 12   202 ms   218 ms     *     ae-5.r24.snjsca04.us.bb.gin.ntt.net [129.250.3.146]
 13   206 ms   202 ms   207 ms  ae-4.r00.scrmca02.us.bb.gin.ntt.net [129.250.7.57]
 14   209 ms   192 ms   202 ms  xe-0-1-0-1-1.r00.scrmca02.us.ce.gin.ntt.net [192.80.16.2]
 15   211 ms     *        *     204.2.229.230
 16     *      183 ms     *     204.2.229.105
 17   206 ms   174 ms   167 ms  204.2.229.105

Trace complete.
Everything is fine until it jumps onto NTT's servers where the reliability of the connection falls dramatically.