The milk pipework has come loose from the milk valve holder, so water is leaking out during the rinsing process.
Insert the milk pipework into the milk valve correctly:
Insert the milk pipework into the milk valve on the left and right-hand sides. Push the connecting pieces into the silicone seal as far as they will go.
Check that the milk pipework is snug against the housing and that the cover can be easily attached.
If necessary, turn the milk pipework toward the back at the connecting piece on the right-hand side.
