Both "That tag does not exist" and "Please provide a tag." messages are not displayed

[emilghittasv]

Preconditions
Sign in to SUMO with an account that has the necessary permissions of updating questions tags.

Steps to reproduce
Steps to reproduce the behavior:

1. Go to any posted forum question (example: https://support.allizom.org/en-US/questions/1458071)
2. Try adding a tag which does not exist.
3. Click on the "Apply" button without adding any data inside the "Apply a tag" input field.

Expected behavior
Step 2: The "That tag does not exist." message is displayed above the "Apply a tag:" section.
Step 3: The "Please provide a tag." message is displayed above the "Apply a tag:" section.

Actual behavior
For both step 2 & 3 no error message is displayed.

Screencasts

Desktop:

• OS: Windows 11
• Browser: Firefox

Additional context
I've managed to get the "That tag does not exist" message displayed only once after stopping an unresponsive script while the "Apply a tag" dropdown menu was in the process of populating.

Unfortunately I couldn't reproduce this. I'll try again a couple of times to see exactly which script block facilitated the message to be shown.