RBR40 - Printer offline and network shares dropping

What Firmware is currently loaded?

V2.3.5.30
What is the Mfr and model# of the ISP modem the NG router is connected too?
UBEE e31u2v1
What is the size of your home? Sq Ft?

Office - <1500
What is the distance between the router and satellite(s)? 30 feet is recommended in between them to begin with depending upon building materials when wirelessly connected.

25 feet

What channels are you using? Auto? Try setting manual channel 1, 6 or 11 on 2.4Ghz and any unused channel on 5Ghz.

2.4 ghz - Auto 5ghz - 48
Any Wifi Neighbors near by? If so, how many?

1 - near, but not overlapping.

Try enabling Beamforming and MIMO(MIMO may or maynot be needed) and WMM. Under Advanced Tab/Advanced Settings/Wireless Settings

They are

Try disabling the following and see:
Daisy Chain, Fast Roaming, IPv6 and Set 20/40Mhz Coexistence to 40Mhz only. Save settings and reboot the router and satellite(s).

They are.

As I said - rebooting the network seems to allow the wireless device to see the remote satellite and connected devices.  The issue is not with connectivity dropping.  The devices on the satellite are rock solid, always connected to internet and can see other resources on the network (another network printer), but cannot see the wireless devices either.  When it is working then the satellite can see a network share I setup for testing on the wireless device connected to the main router and vice versa.  However, usually after a few hours, the connection drops and cannot be reestablished.  This also occurs if the wireless device leaves the network and rejoins (I leave for a meeting and come back).  SUPER FRUSTRATED.

It has dropped since I set it up.  Prior to setting up the share we occassionally had printer issues but those were transient and not critical enough to investigate properly.  The network share is for a shared instance of Quickbooks and causes the remote session on wireless to hang and drop when Orbi freaks out.  Meanwhile the local instance, which is on the satellite, has a rock solid connection to internet.  We also run VOIP through the satellite and no issues at all.

The firmware was updated through the auto update tool.  I check for updates monthly.

I went back through my setup and made sure that I have address reservations setup with MAC and name configured.  I did not change anything but hit 'save' when exiting the settings screen.  The system did not reboot.  But then the network share connected and was pinging successfully again.  Could be a coincidence - the network share comes up randomly and does connect while on wifi, but then drops after a few minutes.

And yes, I know connections to network shares can be a bit flaky under wifi and Quickbooks is a bit sensitive to small amounts of packet loss to network shares - BUT this issue the network share goes down completely, disconnects, and unable to even ping the server at all - destination host unreachable - until the system reboots or a random interval of time (several hours typically) passes.