Poor Tipsey
it could be worms.
How often do you worm her?
Was she done every 4 weeks as a young kitten?
Did you use a shop wormer eg bob martin?
Fleas carry tapeworm so you should deflea with a vet grade product too.
How much do you feed her? Overfeeding can cause diarrhoea.
Hormones can upset tummies so you could look into getting her spayed asap.
Is she maintaining her weight and growing? I would get her vet checked and a stool sample sent off to see if she has any bacteria in her gut thats causing a problem, Campylobacter is something that causes foul smelling poo