This is according to a tweet by the company who states that for the upcoming patch, it happens to land during a tournament which means that they’ll be delaying its release until the event is over. It is assumed that this will be Valve’s approach from here on out with regards to release of patches whose release might fall during an ongoing tournament.
For upcoming Majors where the Thursday patch would land during the tournament, we will instead be releasing the patch at the end of the event.
— DOTA 2 (@DOTA2) April 28, 2018
This follows a previous event, the Epicenter XL tournament, in which Valve released a patch in the middle of the tournament which messed up the entire event as players had less than a day to adapt to the changes that Valve made. While the average player might not necessarily feel the impact, when it comes to the eSports scene, every little change can have a huge impact.
For example cooldown of a particular skill might have been increased by a second, which doesn’t seem like much, but it also means that during the heat of the moment, players will have to deal with that extra delay which could be the difference between victory and failure. That being said, hopefully Valve’s new approach towards patch releases will be taken into consideration by other developers in the future.