My none verbal 21 month old keeps bringing me her beaker as she usually would when it's empty to ask for a drink and then she starts crying and hitting me. The beaker has water in so I don't know why she's crying and getting upset about it. I've tried emptying it out and refilling it for her, putting juice in it instead of water, putting milk in it and taking the lid off so she can have it without a lid or splash in it. Nothing works and she just has a meltdown about it, she won't drink anything from it when she gives it to me, doesn't want me to drink from it but also won't let me put it down because that upsets her more. This has been happening several times a day now for 4 days.
What could it be and how do I fix it?