So there IS a problem after 6.33. Please help me to solve it.
You're not right
Having problems after 6.33 with a PPPoE AC doesn't mean there are problems with pppoe specifically on a given ROS more recent version.
ROS evolves and there have been
heaps of significant changes since 6.33 on all ROS areas,
two years and a half has passed since then! Which was the more recent previous version you downgrade from?
Warnings to changes that require setup adjustments can be found on the
changelog archive; the
ROS 6.xx is released! threads may contain useful info too.
I confirm absolutely same problems on my routers.
Heard about same problems even on 1072 with 1k PPPoE sessions.
I have even OSPF neighbors disconnects sometimes.
What that may point to is unstable L2 on your network. Unless there's pristine L2, you'll experience PPPoE (and all sort) of related problems and unstability.
Did you watch Janis Megis presentation? because there's exactly an interaction between non properly setup OSPF on a PPPoE AC that causes exactly what you describe.
I manage CCR1009's with 500, 800, 1000 PPPoE users, average load rarely exceeds 20-30%. 6.39.2, 6.38.7... I advise using latest bugfix.
Unless you post relevant config, topology, scenario conditions it will be impossible to help you. I asked twice for ROS and Firmware versions and still, you don't post those details, but demand help? No one has crystall balls here...
Clinging to obsolete ROS versions is not a wise choice. I think the fastest route to fixing your specific problem would be hiring a consultant to look at your live router.