If you are covering the plants unnecessarily with plastic bags, this is a major issue.
Temps inside the bag will be 5-15 degrees warmer than outside with close to 100% humidity as well.
Remove the bags asap, cannabis is not a rain forest plant and does not need artificially high humidity.
Also, without air movement, your plants can not get rid of waste products/transpire and this is the reason for the funny growth patterns.
Soil is saturated too, meaning limited oxygen to the roots, something the bags will also prevent, that is, oxygen getting to the roots.
Cannabis does not need to be living in mini "sweat lodges".
Hope this helps, Organoman.