It would help you a ton if you would use this in your spamming macro on your tank

#showtooltip SpellName
/console Sound_EnableSFX 0
/use TrinketName
/console Sound_EnableSFX 1
/run UIErrorsFrame:Clear()
/cast SpellName or /castrandom Spellname

This will silence all those errors and get rid of the item/spell not ready popups in middle of your screen.

Hope this helps