Rinsing cycle at start up is electronically programmed function. Unplugging is a temporary solution.
Jura will not sell parts or offer any guidance.
I could look into more details to find an answer but the model Capressa 50 is not listed in my Data base. Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/edward_bbd2c7ff4ee1828a
You really don't give which machine - but here is link to company product support. Maybe they will have product manual to help trouble shoot issue. Sorry could not of been more help
Product Support