Click on your profile icon at the top right corner of your browser.
Click on Add +
Create a dedicated profile
It will avoid the situation when you have one profile logged in within your browser and one profile logged in within Google Docs or Google Sheets. In the current way Google has built its add-ons system, this is the simplest manner to use your add-ons without conflict.
Otherwise, you can try logging out from your account or use private windows to use Labelmaker, but the above solution will be the easier for you to manage multiple accounts.
Let us know how it goes,
Jean from Labelmaker