Why is one of my switch ports orange/blocking, and should I "fix" it?

Because a Layer 2 triangle without STP is a broadcast storm generator. Ethernet frames have no TTL: one broadcast in a loop circulates forever, multiplying at every switch until the network melts (and MAC tables flap as the same source appears on multiple ports). Spanning Tree's job is to compute a loop-free tree: elect a root bridge (lowest priority, then lowest MAC), give every non-root switch one root port (best path toward root), one designated port per segment — and block whatever remains. Your orange port is the calculated sacrifice; the redundancy isn't gone, it's standby. Unplug the active uplink in the lab and watch the blocked port take over (~30s classic STP, ~2s with RSTP). The only thing to "fix" is which port blocks — set bridge priorities deliberately so the root is your core switch, not a random access switch.