Issue with Ignis ADL348, draining failure?

Hello everyone.
I have a Ignis 348 which I am not sure how many years of service has had since it belonged to the previous renter of the flat I am at now. At first everything was ok. Then a small problem which was not apparent at first try became gradually apparent, being only occasional at first up to becoming very frequent, I would say constant, now.
I have searched the forum and found a similar question but I couldn’t find an exhaustive answer there.(dishwasher-forum/humming-but-not-cleaning-ignis-adl348-t55855.html)

At first, sometime during a program I would note the dishwasher emitting a strange rumbling sound clearly indicating an issue. I would stop the program, open it to find collection of water on the bottom and this plastic tube (which is inside the dishwasher, just to be clear) carrying water to the top hose dislodged from its natural two holes. I would reattach it, restart the program; the rumbling would cease and everything would run smooth. Then I began paying attention before running any program that the tube be firmly attached to its sockets, and if i did attach it firmly the programs would run fine. It was also cleaning fairly well.
Then, only recently the situation has gotten a lot worse. The tube now detaches almost immediately after start. Stopping, reattaching and restarting doesn’t solve the problem as the tube immediately comes off again. This basically renders the dishwasher completely useless.
What I don’t understand is if this tube is the cause of the problem or only a consequence of some other issue. To me it seems like it is designed to bring clean water to the top hose to be sprung on everything, so I don’t see how it could be related to draining the dirty water at the bottom.

I’d appreciate any sort of advice. Thanks in advance.