.... "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