It never bothered me, but with 23.05.2 on the DL-WRX36 2.5G port both amber and green LED's are solid on by default even with no cable connected.
This may be a tough crowd to find someone that has not yet obliterated their OEM firmware flashing OpenWrt to confirm OEM behavior by test 
Ad copy and labels for various 2.5G switches with only one each of green and amber LEDs like the DL-WRX36 indicate: a) LEDs off for no link, b) amber is solid for 100/1000 link and blinking for activity on same, and c) green is solid for 2.5G link and blinking for activity on same. Absent confirmation from someone with OEM firmware, that would at least be a step in the right direction.