The primary concern highlighted is the necessity for these transactions to achieve almost guaranteed mining to prevent operational problems. Further elaboration on this point reveals an agreement on the need for OP_EXPIRE transactions to possess a sufficiently high fee rate. This requirement ensures their inclusion in the next block to be mined, aligning with the initial concerns about ensuring reliability and functionality in the blockchain's operation. Essentially, both parties acknowledge the critical importance of optimizing transaction fees to secure timely mining, underscoring a shared understanding of the challenges faced by OP_EXPIRE transactions in maintaining system efficiency and effectiveness.