it seems to happen the most between the hours of 2-9PM, but that's also more likely the time a user would be on and notice something so I wouldn't suggest its time bound.
Channel change requests happen because the CMTS is trying to balance the load. This activity is most likely to happen during peak hours.
If not fixed, the problems will likely stop once TWC figures out how to get the upstreams bonded, removing the need for channel changes on bonded modems.