While the position on cannabis of the MFP, led by Pita Limjaroenrat, is less clear, as reported by Australian Finance Review, the leader of the Pheu Thai party, Paetongtarn Shinawatra, has taken a firm stance on cannabis and said that she doesn't want his children to grow up in a country where drugs are easy to find, and cannabis is liberalized, as reported by Bloomberg. Furthermore, the Pheu Thai party aims to reclassify cannabis as a narcotic while preserving its medical use.
This is probably used as a bargaining chip in coalition building.