Every command executed from a sign-clickEvent requires operator-permissions

I tried to use the /trigger command inside the clickEvent of a sign.

{Text1:'{"text":"Set Team","color":"dark_red","bold":true,"underlined":true,"clickEvent":{"action":"run_command","value":"trigger team set 1"}}'}

Expected Result

-> The player without any op-permissions can click the sign to execute the command.

Actual Result

-> The player needs to have op-permissions to execute this command by clicking on the sign even though it is a command that usually doesn't require any permissions.

Since executing these commands via klicking on a JSON text in a tellraw or a book works I expected it to work in signs as well.

Additional Information

• I made sure to constantly enable the trigger objective via a ticked function

• I tested other non-op commands like /me and they also don't work in signs