Krups EA8108 leaks into drip tray

Hello everyone,

I've bought a used Krups EA8108 machine, and it leaks 80 percent of the hot water into the drip tray. The other 20 percent goes into the cup. Initially, I thought it was a problem with the piston or its gaskets, so I bought a replacement, but it did not help. If anything, it looks like less water comes into the cup and more into the drip tray.

I have opened the sides and checked while running the machine - it seems like hot water is coming down from the distributor into the drip tray via one of the transparent hoses. I've checked the hoses that are easy to remove but did not find any blockage there. I couldn't check other hoses as they are hard to remove.

What could be the issue? The water is hot. What should I check next?