Did you try the suggestion you got: to reseat the tip (removing and reinserting). This issue happens because the tip permanently activate the pressure sensor - (hence you wont see it using brushes that paint faintly). Reseating the tip should help if the pen is not broken.
#Issue with non remarkable EMR stylus
tawdry flax
tight atlas
I still think it could be a defective pen, or a software update breaking compatibility
tawdry flax
No, a software update could probably not break the compatibility with an EMR pen.
The way to fix it is (as was already mentioned) : try changing the tip or just remove it and insert it again. The issue you encounter means that the tip is all the time pressing on the pressure sensor. Try removing the tip, al together, and see if the pen still writes. If it does, the pen is broken, if not, you should be able to put the tip in without it pressing on the sensor.