Why does an RCD work when the washing machine is working?

Hello! The problem with the operation of the washing machine: RCD 25A is triggered and the apartment is completely de-energized. The machine is connected to an outlet in the bathroom. But, when I plug it into an outlet between the bathroom and the bath through an extension cord, everything works without an RCD trip. Six months ago there was a short circuit in one of the 4 fixtures in the bathroom due to moisture (the transformer burned out). Everything, including the wire, has been replaced. Everything began to work fine. A month later, the RCD started to work again. He opened the rack ceilings and changed all the twists to the terminal blocks. No malfunctions were visually detected. But the RCD stubbornly works 10-15 minutes after the start of the wash. It is necessary again to connect through an extension cord to another outlet. I opened the outlet in the bathroom: visually everything is normal, no burning, bare sections of the wiring were found, everything is securely fixed. Please help me figure out the reason for the operation of the RCD.