Throwing up clear liquid

My nearly 6 month old has started throwing up clear liquid over the last week or so, it’s only happened I think 3 times but I’m just confused as she doesn’t drink anything other than breast milk, but she has started purées and some solids. Has anyone else been through this or know what it could be? I’m not too concerned because she seems absolutely fine in herself and doesn’t cry when it happens or anything, and there’s nothing else raising any red flags, I guess I’m just more confused than anything