DS-920+ causing internet interruptions with Deco X55

[Enquiries]

I’ve been troubleshooting intermittent loss of internet. I have Deco X55 x3, Main hooked to Cable modem and two others creating a wireless mesh in my home. Whenever I connect the DS920+ to the Deco (directly or through a switch) I get intermittent drops in my internet connection. Tech support from China has been a struggle due to hours and language. Tech emailed me today and said
"I guess that the NAS sent a flow control pause frame to Deco, which caused Deco to enter the flow control state. You can consult the technical support of NAS to see if there is a way to make NAS not to send pause frames. "

Does this make any sense? If so, any recommendations of how should I change my DSM networking settings? Currently running DSM 7.1.1-42962 Update 5

[ed]

Yes, this could be the case. You could also make sure JAMBO frames are set to an equal value compared to other network devices.
But Synology support will help you better than me.
P.S. something to try via SSH
ethtool -A <interface> autoneg off rx off tx off

Replace <interface> with the name of the network interface you want to modify. For example, if you want to modify the first LAN interface (eth0), you would type:

ethtool -A eth0 autoneg off rx off tx off