Reproduction steps (on an unaltered default theme)

• Go to your Inbox
• Click 'Disable my inbox' at the base of the message listing
• a prompt appears indicating the following, click OK...inbox now disabled

Quote

Disabling your inbox prevent others (except staff members) from starting a new conversation with you. You can still start a conversation with others, and reply to existing conversations.

• On a desktop...
  • the Messages icon now indicates that the inbox is disabled (greyed out/hover message displayed)
  • Click the button and the inbox appears.
• On a mobile...
  • tap the 3-line/burger menu
  • the Messages icon now indicates that the inbox is disabled (greyed out)
  • tap the icon, and the inbox appears
  • However, that's not the only way to get to the inbox...
    • tap Account -> Messages
    • a prompt appears indicating the following:

Quote

Your messenger is currently disabled. Would you like to re-enable it?

Click OK and your inbox is now re-enabled.

 

 

Im not sure this is really a bug to be honest. It does this as It's a clickable link to enter the inbox, rather than (as with the icon) a dropdown

I didn't state it was a bug.

Just offering it up - do with it what you will.

I will certainly bring it up internally, however to me its likely due to the difference in action that would result normally from those links