What is the cause of the errors? PoE is just a DC voltage and current transported over the same wires as the data which is an AC signal.
Does the power draw affect the data signals directly?
I’m a little confused by the PoE test there. Even 802.3bt Type 4 (PoE++up to 100 W) would only have 1.4 A passing through the cable. Presumably the test was only putting 12 V across the pairs?