In most machines the disinfectant circulates in all the internal tubing and the machine is protected from water contamination by a water treatment system (filter, UV, boiling…..). Therefore if the machine is well designed (no dead zone) and the disinfectant efficient, what's the need for a special self disinfection cycle?
Most machines can disinfect endoscopes, but all machines can also contaminate an endoscope.
The contamination can be caused by a failure of the water treatment system (filter or UV break down), or by a back contamination from the machine to the water treatment system during the cleaning or during a long period of non use of the machine.
Once the water treatment system is contaminated, it will contaminate the endoscope at each final rinse and leave germs in the internal tubing of the machine that can develop a strong biofilm very difficult to eliminate. In most machine there is usually no way to disinfect the water treatment since it is normally out of the disinfection circuit.

See: Self disinfection cycle efficacy evaluation

Soluscope has a very original self-disinfection cycle. Concentrated chlorine (9.8%) is manually poured in the basin. This chlorine is diluted, heated and circulates in all the hydraulic circuits before being drained backward through the filter. Then the Soluscope rinses and does the same with 0,2% glutaraldehyde, without any rinse after draining so that the filter and the bottom of the basin remains with diluted glutaraldehyde until the next cycle is performed. This cycle not only disinfects the machine but also the filter, ensuring that everything is disinfected contrarily to other machines which cannot disinfect between the machine and the filtration system and the water treatment itself.