SMS notifications sending duplicate messages — bug?

Hi everyone! Our team started noticing this morning that customers are getting **two identical SMS messages** for every notification we send out — arrival alerts, job completion, everything. It's causing some confusion and a few annoyed customers calling back to ask why we spammed them. We haven't changed anything on our end that I know of. Is this a known bug? We're on the standard plan and using the default SMS templates. Thanks so much for any insight — really appreciate it!