Glow inc sac removes the text on signs

I've noticed another bug when it comes to the signs, I noticed that when you apply a glow inc sac to the sign. The text disappears and don't appear to come back. I did see that I got the glow inc sac back to my chest somehow which makes no sense but I have to redo the sign to get the text back, but if I apply the glow inc sac again it disappears. So please fix this, I would love to have my signs all glowy again.