What does alternating amber/red mean on eth port on GSP260 switch?

It is using poe to power LHGG on that port.

Gif of the switch itself with port 3 blinking amber / red: https://imgur.com/a/6mMN3UU

Perfectly normal that alternating amber/red.
Non PoE use: green flashing with traffic
PoE out: red + green flashing with traffic.
Looks like red+green gives amber ... . The LED' light is not well separated neither.

Okay different cable on port 5 is using PoE as well but it is flashing green? Connected is a hap ac3. When i take a cable from port 1 however and use it for ac3 it starts flashing amber / red. Same goes for LHGG. The cable works fine it negotiates 1Gbps ethernet connection and shows no faults. However in a recent survey i found out there are some retransmission and out-of-order tcp packets on the network. Posted here: viewtopic.php?p=886995#p886995

Port 1 of the RB260GSP has no PoE out.
If PoE out is sending energy depends also on the device attached (proper resistors need to be installed in the used device-port to absorb the energy. This makes it a "PoE in" port)
Plug the cable in port2 of a hAP ac2 and the status will be "short circuit"

Status of PoE out is in the web-management panel.
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Sorry did not specify i took the cable from port 1 and used it in port 5. Port 5 has the ac3 attached to it. So basically i changed the cable between ac3 and port 5. Before it was flashing green and now amber/red. I really think that i might have faulty cables or cable ends. Everything shows like it is working as intended but there still are problems. Some frames go missing when loading pages sometimes there is just a random hang like there is a TCP timeout or something similar.

I really think that i might have faulty cables or cable ends.

Looks indeed like a faulty cable. SwOS has no logging unfortunatly, but RouterOS has, and there is a "Cable test" option. (Don't know what it tests, never used it.)