We have just been informed, today, Tuesday 25th July 2017, that countries with 90 days bilateral agreement with Thailand, namely, Brazil, South Korea, Peru, Argentina and Chile will not be stamped OUT/IN for anolther 90 days visa exempt at any Thai-Cambodian border. It is OK to do a border bounce if they are holder of multiple entry Tourist or Non Immigrant Visa. Thank you
TLDR : Answer Summary
As of July 25, 2017, citizens from Brazil, South Korea, Peru, Argentina, and Chile can no longer receive an additional 90-day visa exemption when crossing at Thai-Cambodian borders if they are not holders of a multiple entry Tourist or Non-Immigrant Visa. There are ongoing discussions among expats regarding the possibility of similar exemptions at Malaysia or Laos borders and the status at the Ranong border.