https://userapps.support.sap.com/sap/support/knowledge/en/3568942
3568942 - Hyphen prefix in SMQ2 queues | SAP Knowledge Base Article
Queues in SMQ2 are appearing with a hyphen prefix, such as -BTZ*. Typically, queue names appear without a hyphen, like XBTZ*.
sap knowledgehyphenprefixqueuesbase