RBR50 performance degradation after 2.5.0.38 firmware update

Hi everyone,

Updating my Orbi RBR50 router and RBS50 satellites to the latest firmware release package (2.5.0.38) seems to have resulted in a significant deterioration of my network's performance.

Before I explain further, let's forestall any well-meaning but useless "advice" by noting that I have already tried the usual "Orbi update sucks" diagnostic steps including:

• Factory resets of the Orbi router and all satellites in the network (tried 3x).
• Clean installation of the Orbi router and satellite firmware from the latest-available package on the support portal's downloads area (tried 2x, on 2.5.0.38 and 2.5.0.40 hotfix).
• Verified that the network performance falloff is occurring "south" of the WAN connection between my cable modem and the Orbi RBR50 router via on-router Speed Test, wired connection direct to the cable modem, and independent corroboration via a service call from one of my ISP's service techs to confirm that the network "north" of the cable modem is functioning normally and experiencing no performance falloff.
• Verified that there have been no changes to the configuration or operating environment in which my Orbi system is running except for the update to 2.5.0.38 (and 2.5.0.40).  Even the user-configurable settings in the Orbi router were manually reset to what they were before the firmware update.

After the Orbi mobile app announced to me that there was a pending update (2.5.0.38) and I gave it the go-ahead to install said update and then performed a full factory reset because I hadn't forgotten what a pain in the arse previous Orbi updates were, I began to notice a significant degradation in the speed and stability of my home network.

Once my Orbi system was factory resetted and reconfigured post-update, I noticed almost immediately that the network south of the Orbi was significantly slower on 2.5.0.38.  The in-router speed test reported (within the usual margins of error) the correct full performance of my cable internet connection: ~360Mbps downstream, ~25Mbps upstream.  Speed tests run from client devices (wired AND wireless) on the Orbi network reported virtually identical numbers prior to the 2.5.0.38 update regardless of whether they were connected to a satellite or the router directly.  Post-update, both wired and wireless client devices began reporting 30-80% lower speeds on the same speed test client using the same servers.

Other symptoms noted after the update to 2.5.0.38 included periodic spikes in lag and packet-loss rates.  Pre-update, my typical ping while gaming online was between 32ms and 37ms.  Post-update, my ping now hovers between 44ms and 70ms and jumps (every few minutes) to around 160ms to 250ms with a current record of 890ms.  That's bloody unplayable.  Also, while running Discord, I noticed my upstream ping (typically around 21ms) jumping to over 250ms every couple minutes accompanied by my packet loss rate going from 0.0% to anywhere from 10-25%.

After multiple factory resets, reinstallations of the firmware, etc., the problem persists.  The issue seems to exist in the Orbi itself between the WAN and LAN interfaces.  The Orbi's WAN-facing speed test doesn't experience the slowdown seen by the devices connected using gigabit ethernet or 5GHz WiFi, and I confirmed that its speed test is reporting correctly by directly connecting to the modem using gigabit ethernet and by taking the modem out of bridge mode and connecting to its 5GHz WiFi and running the same speed tests to the same servers and getting the expected full performance of my connection.

I don't know if the Orbi has a hidden QoS client running or something along those lines, but something in the 2.5.0.38 (and in the 2.5.0.40 hotfix) firmware is broken to the point that it's preventing connected devices from getting anywhere near the full network speed of the WAN even if they're the only client on the network.

If anyone has any useful advice not on the list above or Netgear needs/wants any relevant logfiles from my system to help with developing a fix, I'm all ears.