Message fails to send if it contains word "cursor", a colon ":", and brackets "()"

Description:

I encountered a case where Rocket.Chat fails to send a message. The message stays grey in the UI and is never sent. I am not an admin and this is not critical for me, but I thought reporting it might be helpful.

This bug appears to occur when the message contains the following three elements in this order:

1. the word "cursor" (case-insensitive)
2. a colon ":"
3. parentheses "()" (empty or with content)

Steps to reproduce:

1. Open a chat in Rocket.Chat.
2. Type a message containing the word "cursor", followed later by a colon ":" and parentheses "()".
3. Attempt to send the message.

Example minimal message:

asdf cursor asdf: asdf (asdf)

Expected behavior:

The message should be sent normally.

Actual behavior:

The message remains grey in the UI and is never sent.

Server Setup Information:

I am not admin, just a regular user, so I have no idea on the server side.

• Version of Rocket.Chat Server: unknown
• License Type: unknown
• Number of Users: unknown
• Operating System: unknown
• Deployment Method: unknown
• Number of Running Instances: unknown
• DB Replicaset Oplog: unknown
• NodeJS Version: unknown
• MongoDB Version: unknown

Client Setup Information

• Desktop App or Browser Version: unknown
• Operating System: Windows 11

Additional context

I originally encountered this when writing a message like:

The Cursor AI costs go to project: MyProject (123456)

The message failed to send until it was rewritten to avoid this pattern.

Relevant logs:

No logs collected.

No file or test is named. Start by reproducing the example in Rocket.Chat's chat composer and tracing the send path for messages containing "cursor", a colon, and parentheses. Done means the reproduced message sends normally and a regression test covers the reported pattern.