... "It was then filtered and transfered to the two demijohns ..."
If you filtered the wine without sulfite protection, this is most likely oxidative browning.
... "Yes, both batches taste a bit like watery cider"...
When you say "watery cider, do you mean it is sweet like cider??
If it tastes sweet like fresh apple cider, then your fermentation stopped before completion. This could be the result of a ML infection especially if there was no sulfite present. If your purpose was to make a dry wine then you'll need to sulfite to about 60ppm to knock out any residual bacteria, add yeast nutrient and re-innoculate with a strong bayanus yeast like 1118.
CHEERS!
Aaron