I've read «about dampening material that disintegrates and destroy the PCB» only in the context of BL8000 Mk1 & a range of Mk2.  Never about BL6000. Our BL6000 are now 27 year-olds, still as beautiful as the day we bought them in preparation for our wedding and first home.  At some point circa 2010, one of them started making a disagreeable reverb.  I sent both BL6000s to the Sound Smith here in the US and he replaced the cardboard speakers, if I recall correctly. No issues since.

Thanks thats good to hear 😀 I would also have expected problems to have showed up by now if there were any

I have given my Beolabs 6000 serial number 140..... a Maintenance service, sound was 'good' . When removing the speaker cloth, nothing seemed to be wrong, but as soon as you touched the woofer rubber suspension, it completely crumbled. totally perished. Then I removed the woofers speakers to look at the condition of the internal damping material, but not only after that, also at the air density of the seal of the speakers between themselves and at the aluminum housing. ( Previously I renovated a Beolab 8000 whose damping and sealing material was completely decayed. what a sticky thing. PCB was affected there.) With the BeoLab 6000, the quality of the damping material was equivalent, so completely perished. Only with the Beolab 6000 is the damping material partially glued to the housing, so it cannot sink towards the PCB as with the Beolab 8000. But still, small pieces had ended up on the circuit board and connectors, which could have caused damage in the long run. Also, damping material completely removed, including the mutual sealing edges and completely renewed. Because the rubber suspension of the speakers was also completely broken, these speakers also replaced (you can only replace the defective rubber suspension instead of renewing, but I have opted for total replacement.) For the coming years, the quality feeling and the sound, especially the midrange and the bass are sublime again.