Fluid Brush Tool Only Works Sometimes

I'm new to Animate and whenever I use the fluid brush tool, it works the first time I use it, then it doesn't work again unless I change something in the brush settings. (ex. stabilizer, brush size, etc.) 

Not sure if this matters but I'm using the ASUS - ROG Zephyrus G14 AMD Ryzen 7. It has 16GB Memory and NVIDIA GeForce GTX 1650 - 512GB SSD.