Miele S8 / C3 Vacuum cleaner - Bag full indicator problem. (Unresolved)

My Miele S8730 (part of the s8 / C3 complete range) has developed its first problem, and I think this was also a common problem with the previous S5 range as well. I noticed this problem the other night and in this video I attempt to explain the problem, then strip the lid down to find out the cause of the issue, and see if I can fix it, which in this occasion, I did not, as the issue re-occured again afterwards. I'm not sure how widespread this problem is with the C3 range, or if it was confined to early models like the one in my video, which was made in July 2012, making it a very early example. I guess this was an early "teething problem" with a completely new model, as the S8 was only released in 2012. As the machine has been boxed up most of its life, and only started being used quite recently, this issue with the bag full indicator may have otherwise come to light a long time ago with my machine.