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.