Hi there.
I personally wouldn't increase her milk as she is already having a fair amount and tbh you might even consider cutting one of those bottles to increase her appetite for solids (most LOs are down to 2 bottles at this age and it is advised to drop all bottles at 12 months and move to a cup). The holding food in mouth, i have not heard of, but it sounds like lack of appetite for the food, she's just not hungry for it. I would reduce down to 2 bottles, WU and BT, switch the 3rd bottle to a solids snack with sippy cup of water and at other meals if she holds food in her mouth just say 'looks like you're full' and end the meal. She's not going to starve herself but if you keep cajoling her or tricking her to eat by offering drinks etc there could end up being a power struggle over eating which you don't want. Babies and toddlers quite often have a small appetite and seem to be able to live of fresh air. portion sizes are much smaller than we tend to think, plus we see how much they *can* eat during a growth spurt and can then have an expectation for them to continue eating that amount daily, long term, plus when they are teething they often cut their food intake and have no adverse effects as they just make up for it when they are ready. So, really I would back off and just continue to offer healthy solid meals and let her eat whatever amount she wants without worrying.
It would be a good time to increase offering finger food. At this age LOs can be joining in with regular family meals and seeing you and the rest of the family eating the same foods can be a great motivator to join in, humans are social eaters, babies like to have just what mummy and daddy have.
hth
