Nope. Just using logic.
Cat cable does not have shielding between pairs. So there will be electrostatic and electromagnetic crosstalk. Just spit-balling here but I think electrostatic will be dominant if the impedances are high and electromagnetic will be dominant if current is high. I don't think the typical line input impedance of 10K is particularly high wrt capacitive coupling so I think the primary concern would be electromagnetic coupling. In that case, a 600 ohm load would be about as low as one would expect for a line level signal. Lower levels would equate to lower current. So high level signal into 600 ohms running next to a 10K line is probably going to generate about the most electomagentic coupling that you would expect to see in reality.
Now is that crosstalk higher than your noise floor? If you have an otherwise very quiet source running into a converter, then I would be willing to bet a roll of toilet paper that you would see it on an analyzer.
UPDATE: Actually I must be wr-wr-wrong about this. All of the cables Whoops is posting about below use shielding that would only help with capacitive coupled crosstalk. In particular, SFTP is foil around each pair and then foil and braid around the bundle. But I don't think the extra foil would create enough space to reduce electromagnetic coupling. In regular snake cable each pair has a vinyl jacket around it that creates a relatively large amount of space (2x jacket is 2-3mm maybe) between the pairs. It would be interested to measuring the difference in crosstalk between a conventional CAT6 vs SFTP CAT6 vs proper snake cable.
