I went to Pathumthani immigration this morning to extend my non-b and all they did was take a photo of me with their cellphone after I had given them my paperwork and money. We were not allowed to interact with them as we had to stay outside. In and out in an hour. Afterwards, at the place where u renew your work permit it took about an hour. They have separated the ques into 2 sections. One for workers and one for teachers.
TLDR : Answer Summary
A user shares their experience extending their non-B visa at Pathumthani immigration, describing a quick process involving photo capture and minimal interaction, taking about an hour. They also mention a separate queue system for workers and teachers when renewing work permits.