A cable plugged into a switch but unconnected on the other end, might lead to any problem in a "noisy" environment (industrial)?
It's short, 50 cm, but there are motors, inverters, power supplies very close to it.
A disconnected cable shouldn't be able to cause problems.
The twisted-pair wires are connected by pulse transformers, isolating the cable from the connected devices. However, with a shielded cable and non-optimal grounding of the cabinet components, strong noise from the shield might be able to disturb system ground and cause stability problems. I'd use an unshielded cable (UTP).
On the data level, an unconnected cable cannot possibly get a link up and introduce garbage data. The link can only come up by negotiation using link pulses (FLP) - this is practically impossible through noise.