Waterproof agent is composed of hydrophobic substance; it needs to be emulsifying and diluted by amount of emulsifying agent before use. 
Generally, the emulsifier agent is acid-stability not alkali-stability and reactive dye’s react must under high alkaline condition which same as disperse dye’s reduction cleaning process. 
If the alkali cannot completely removed from the fabric it will cause floating oil when people use the water repellent and it occurred the stick roller problem.
How to prevent:
1.    Reactive dyes: After dyeing the fabric must completely wash off and pH value should adjust to neutral.
2.    Disperse dyes: after reducing cleaning, make sure the pH value is neutral. 
3.    Setting machine: Keep it clean to avoid sticking roller and waterproof spot, test the pH value hourly and make sure the value is below pH5. 

Over all the above points, we suggest the pH value should keep on neutral and the machine also need to keep it clean.
In the meantime, our waterproof agent PENELON 8851 is a very stable agent and it will not easy to appear emulsion breaking problem.