Here is the message from Epic Games:
“We messed up in missing a HUGE part of our patch notes. I apologize. We understand how much time you have invested in building your Storm Shield base, it’s your home, your defense, your vision, we feel that way too. We will be dedicated in providing detailed at patch notes going forward.
In our haste to get this patch out we missed clarifying tweaks to the Plankerton, Canny Valley and Twine Peaks Storm Shield maps. We decided to make change to those maps to improve game balance at upper difficulties. Map changes require us to reset any base you have built. Building materials and traps have been refunded into your Storm Shield Storage, the storage overflows in cases like these so you have every piece of stone, every trap laid ready to be reused. We have to do this to avoid issues with built bases conflicting with the map changes. We know that the time it took to create your base can’t be replaced, we hope that opportunity to rebuild with all your resources and past experience will allow you to make an even better base.
As we move through Early Access we will be modifying the game and making changes to improve the experience, at times this will mean changes that require refunds to core systems like the skill tree, research tree, and storm shields. We are never going to reset your overall progression.
Moving forward we’ll make sure to communicate changes BEFORE they happen.
Apologize again for the confusion.
Source: Fortnite forums