i'm still having the issues as well, i have the ear of the bell guys that have been to my house and they've been giving me the tour of the system and how it works. we've replaced the modems a number of times, we've tested the lines dozens of times and removed anything on the physical line that *could* have some issue.
still no resolution and the links are still dropping over pppoe. no real update for you but still having the issues which seem to only happen after 4/5pm.
it seems from your log that it also drops during the same period as me as well. can you let me know if you connection is stable during the day up to before 4pm?