I can no longer access Event and System logs in Gateway tool

Not sure what device or what method you are using to access it, but if you're using a browser try either clearing the cache or opening up a private window. And of course a reboot of the device, sometimes the management interface daemons running on them crash/lock up. But yes looks like an upstream impairment of some kind, check cable connections and temporarily remove splitters and if you feel up for it try moving the modem closer to where the outside coax comes in. If none of those help yeah you'll probably need to get them to take a look.

@user_59erfv 

Yes. The upstream power is too high / out of spec. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

In an effort to try to obtain better connectivity / more wiggle room, check to see if there are any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage from Home Depot, Target, Wal-Mart, etc. Splitters should be swapped with known to be good / new ones to test.

Also check the coax cable for any damage such as cuts, nicks, abrasions, kinks, sharp bends, etc.

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two-way splitter connected directly off of the drop from the street / pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.

Good luck with it !

Yes, it's normal. The upstream power level and the downstream power level work opposite of each other. When the overall line attenuation is reduced by removing a splitter, the upstream power will become lower but the downstream power will become higher / stronger. It's a balancing act between the two.

If the high downstream power now becomes a problem you could try inserting a -6 dB forward path-only attenuator pad such as this one on the coax port on the rear of the modem to knock that power level down and see: https://www.amazon.com/line-Signal-Forward-Attenuator-FPA6-54/dp/B07882H96R 

It won't affect the upstream power level. 

Channels 1 and 41 are still on the high side. You may want to get a tech out to properly balance the line levels.

@user_59erfv @train_wreck  

These are the right choice for use in mid-split upgraded areas. They start at 85 MHz;

https://www.multicominc.com/product/multicom-mul-fpa85-forward-path-attenuator/ 

Whattaya' gonna' do......