3 years of pressure loss, boiler replacements, power flushes and other contractors carrying out leak detection. It took us 4 hours to complete this! Unbelievable.
I suspect that the copper has been eaten away by self cleaning flux. Bad plumbing practice at installation. May well happen again, under the ‘right’ conditions.
Surely if that much water was leaking from the 22mm, it would have caused more damage than that over the three years. Like your vids, but turn the music down or better still, off!