When glow ink sacs are used on a sign, they make the text render bright but since all signs have black text this has no effect - the text remains black like always. Applying a dye to the text fixes the problem.

What I expected to happen:

I expected the text on the sign to become readable in the dark when clicking it with a glow ink sac, without also needing to dye the text.

What actually happens:

The text on the sign remains black and unreadable in the dark, not appearing glowing at all, when clicking it with a glow ink sac, unless the sign was previously dyed.

Steps to reproduce:

1. Find a dark spot, preferably lock yourself in a cage of tinted glass
2. Place a sign somewhere in the dark spot, and write some text on it
    The text is not/barely readable because it's too dark
3. Click the sign with a glow inc sac
    The text is still not/barely readable because the text was and still is black
4. Click the sign with any dye (except black dye)
    The text becomes readable because it is no longer black, and it glows properly

Video:

https://youtu.be/T2ZFtXpAD1c