High level of T3 timeouts

This does not look abnormal. One or two T3 errors a day is not unusual. It is a downside of using DOCSIS technology that some of the upstream channels are susceptible to noise. If you are getting over 100 a day then it might be worth investigating.

If the figures are now fairly stable, the issue has passed.

We also see similar or bursts of downstream errors logged, often it is no more than an engineer working out of sight at a local street cabinet connecting a new customer. 

The power levels overall, seem to be slightly elevated, I know as long as it is below 50 it’s usually okay.