Foreign objects

An interdepartmental commission conducted an investigation into the causes of the accident, which led to the loss of two satellites. After the second turn on of the propulsion system, the pressure in the fuel tank dropped sharply, and the rated thrust was not achieved. The drop in pressure could be caused by several factors - either the presence of foreign objects in the fuel tank, which could cause the main cable to become clogged, or its mechanical damage.

An anonymous source (a very secret comrade) complained that “there are a large number of rubber gaskets that could break,” and the possibility of a blockage cannot be completely ruled out, although “it looks extremely unlikely.”

Of course it's unlikely...

Last month, Interfax reported that “while repairing one of the units of the Proton-M launch vehicle, specialists dropped foreign objects into an empty oxidizer tank. It took almost a day to locate and retrieve these items. Because of this, it was decided to postpone the launch from July 7 to July 9.”

Or maybe journalists are making things up again?
Preparing a rocket for launch looks like installing a water tap by plumbers from the DEZ.
Or don't they write?