Good afternoon!

I submitted my documents for Non-B 1 year extension along with my wife's Non-o extension in Samut Prakarn immigration. Today was the day to get the stamp for 1 year extension, and after waiting for some time Samutprakarn immigration told, they are ok with documents but Chaengwattana office wants to check all the documents again. Thus, put a stamp again to come back on 28th October. This is the first time we are encountering this.

Is it normal? or randomly they just picked to checked again ?