XS508M sometimes two LEDs remains permanently yellow

let me understand what you did:

you connected your ATV via GS110MX 10Gb Ethernet to the XS505M SFP 10Gb port 

and the XS505M is connected via Ethernet port to your Router RBRE960

So I guess the 10G of your router is used as WAN.

My router is a Fritz Box 7590 and the WAN is direct connected to internet fiber box and Port 4 1G connnection goes to the core switch XS512.

The core Switch XS512 is connected with the XS508 via fiber connection 10G. This connection is done via 2 Moduls Netgear AXM761 and Digitus DK-2533-01-04 LC to LC 1m. This was the most recomended connection to my 10G infrastucture.

All rooms are connected via 10G Ethernet to the Core Switch. I use for all 6 rooms GS110EMX (TV and Office) or MX for all other rooms. My Surveillance Cameras are also connected via GS110MX to the core switch XS512.

On the XS508 I have following connections:

• Port 1-3 only the three Varta connections (Varta1, Varta2 and VartaLink) 
• Port 4 my NAS QNAP677 (10G) and 
• Port 5-6 the Backup NAS QNAP 882 10g and 1G Backup connection
• Port 7 free and 8 Ethernet is free (8 coupled with SFP)
• SFP connected to SFP of Core switch

On the Core Switch XS512 following is cionnected:

• Port 1-6 connected to rooms (port 4 => direct connected to Router 1G)
• Port 7 SMA1 Photovoltaik 
• Port 8 SMA2 Photovoltaik 
• Port 9 SolarEdge Photovoltaik
• Port 10 is my 1G Backup connection to NAS QNAP 677
• Port 11 Surveilance connection (external cameras)
• Port 12 free as coupled with SFP
• SFP connected to SFP XS508 switch

I did not think about trafic ar segmentation, because I did not want to complicate anything. Should I boundle the NAS connections on the CORE Switch and the Smart connections to the XS508? This is the only one could disturb by data transfer to NAS (see Surveilance over night)....

The only thing I could imagine is that one of both two disturbs however the connection 

So is there something I can optimize to avoid any interference due to NAS or Surveilance or IP-TV?

But I dont think the trafic is so high for my 10G environment.... before of that the Surveilance worked via Wifi connection and it was ok. BUt who knows!