Can't apply glyph

I've tried multiple times to apply a glyph effect to a spell, but the glyph stays in my bag and only the spell gets cast. I'm trying on my Warrior to apply Glyph of Thunder Strike, but doesn't seem to apply only to cast constant thunder strikes without thunder.

Is there any solution to this?

Edit: There seems to be a little time window to operate. As long as the spell in the spellbook isn't highlighted it can't be applied. So I have to do some 100% mouse movement and stay still perfectly on the spell in the spellbook. Else it won't apply.
Hey Moustacho,

This is a known issue that is being looked into. Please do report it as bug in-game as well, as the additional information will help with the investigation.

Instead of clicking the glyph from your bag, it might help to place it on your action bar for instead. That way you can have your mouse over the spell in your spellbook and press the keybind to apply it.
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