dispenser bug from locked system

Dear staff,

I don't understand how a dispenser lock from a beefarm from Minecraft Elegance: Next-Generation Honey Farms (Java 1.15*, 1.16*, 1.17+) - YouTube. Is very rare why a dispenser that have that lock stand. 

How I must to solve this problem in redstone terms?

How To Use A DISPENSER IN Minecraft - YouTube lock dispenser theorie.

Further I use 1.21.1 and the server support 1.21.1-1.21.4.

 

kind regards,

espressokofie3