Hello!
Please understand that these seasonal SPECIAL trains are provided to clear the extra rush during peak seasons. Also, bear in mind that these trains are not regular trains plying on the regular routes. Since priority is always given to the regular trains running on a particular route, it's inevitably these 'special' trains which get affected in term of delay. Yes! Railways should make sure to maintain the timings of these 'special' trains as well but with the number of trains running on the existing routes this is indeed going to be a challenge!