Water can't be picked up when using split touch controls. When turned off you can pick up the water, just as expected. Placing down water seems to work fine though.
What I expected to happen was:
Touch a waterblock to pick up the water, with the bucket in your hand.
What actually happened was:
Nothing. The water can't be picked up (note that a full waterbucket CAN place down water when using split touch controls)
Steps to Reproduce:
1. Make a bucket and equip it.
2. Go to a body of water.
3. Turn on split touch controls
4. Try to pick up the water.