There is inconsistent sound-based behaviour with the usage of shears by dispensers on blocks or mobs.

When shears are used on sheep with a dispenser, the sheep shearing sound can be heard (as can be seen in the screenshot displaying the subtitle "Shears click"). However, when a dispenser uses shears on a bee nest or beehive, no such shearing sound is played, despite one existing and being played upon manual shearing. This may also affect the usage of bottles, haven't tested yet.

On a related note, using shears on pumpkins displays no subtitle.