Sometimes the Glowforge is just not cutting all the way through material. Even using brand new proofgrade material with default proofgrade settings.
Pretty frustrating as the only point in buying this material is to not have to fiddle with the settings, also it is leading to wasted material since it randomly just does not work.
Which machine do you have…a performance (basic, plus, pro) or Aura? Have you tried printing the Gift of Good Measure which is the file they use to diagnose? If not, give that a try and record what time you tried it and get some photos of the outcome. Proofgrade materials are guaranteed to work…so if all troubleshooting fails, you can get a refund for your material.
I am using the Pro machine. I went ahead and slightly lowered the speed of the cut, made no other changes, and it cut even less, as well as somehow not even finishing the cut, and shifting the entire cut about a quarter inch off of where it should be:
I suggest cleaning the optics again, and making sure all of the windows are clean - the one on the left side of the machine, the one on the left side of the printhead and the small ones on the underside of the printhead. Slowing your speed slightly should have resulted in a better cut. Since this board is now wasted, do some test cuts after addressing the optics again and see if you have better results. Your cut line looks a bit thick, so make sure you are using set focus and that your lens is properly installed.
On top of what everyone has said - you need to contact support with an image of the Gift of Good Measure not cutting through. They will refund your Proofgrade cost, because, as @Xabbess pointed out, it’s guaranteed to work…but you have to let them know!
If your machine is old and used enough they may have to adjust its internal power a bit. They do get weaker with age and heavy usage. I haven’t run into that but I’m not a heavy user. Others on here have gotten the adjustment.