There are several modems that don't clear the upstream counters after retraining or reboot.
Based on your upstream stats you have:
- 2781 Err Secs, which is a total of ~45 minutes.
- 9421 UAS which is a total of ~2.5 hours when the modem could not get sync.
These may or may not be contiguous. I'm just making the data more reader friendly.
You say that you have only been up for 5 mins. Therefore the 2 stas I highlighted are impossible for 5 mins uptime.
The absolute maximum is 60 per min, so 5min = 300. At that Err Sec rate the line would be dreadfully laggy, making even surfing difficult. Data packets will be dropped left right and center causing web pages with any images or other objects failing to load.
Based on the info you have provided I think its a fair bet to say your modem is one of those that cumulates the upstream error counters.