The hot water is limiting the uptake of water, nutrients and oxygen so it stays wet longer and cools faster slowing down the plants processes.
Since you believe your soil is drying out too fast, cover the top of the pots with cardboard or straw so your not losing as much water to evaporation
Cold water shocks them so they cannot transport the water through their systems making it so they can't drink to transpire until the water warms up. The only way to remove the excess water in a cold soil is through evaporation.....Cold water can also make beneficial microorganisms go dormant so is generally a no-no.
Hot water limits the uptake of oxygen and evaporates faster from the soil so the plant is unable to create hydrogen bonds to transport water, oxygen and nutrients through the xylem and out the stomata's so they dehydrate unable to retain moisture. Hot water can also kill beneficial microorganisms and damage shallow root systems though it can also kill the bad guys too like mealy bugs, aphids, thrips etc.
**fun fact, if you need ice cubes in a hurry use hot water as it cools faster in a phenomenon called The Mpemba Effect: the overall mass decreases as some of the water evaporates as it cools
Room temperature water IS THE BEST because the root zone does not go through constantly fluctuating temperatures and allows the plant to transpire correctly. Lets take a look at the process.....
Water gets added to the soil-> water mixes with nutrients in the soil micro organsisms have broken down -> the oxygen in the water and drying soil makes a bond with the nutrients (opposites attract forming a hydrogen bond through cohesion) -> the roots uptake the bonded nutrients into the xylem through adhesion-> the xylem acts as a straw sucking the water up through the plant -> guard cells surrounding every stoma in the leaves takes in water and potassium ions so they expand to start photosynthesis -> swollen guard cells opens the stoma -> water evaporates through the stoma cooling the canopy while carbon dioxide enters in -> once the plant senses the dark cycle the guard cells release the water so the stoma closes allowing the plant to rest......or reduces photosynthesis if lights on and underwatered causing leaf wilt or if overwatered leading to leaf ballooning.
The rate of plant growth and development is dependent upon plant transpiration, the temperature in the environment as well as, the plants root zone which needs to stay ~5-10f cooler than the canopy for efficient growth and canopy cooling capability.
The plants must strike a balance between conserving water and bringing in sufficient amounts of CO2 and oxygen through the soil therefore we must strike a balance of watering frequency/amount, adding nutrients at the right time, temp etc....it cannot do so if the environment is constantly changing whether it be in shock, cold/hot roots, too hot, over/under watered etc.