Water gone, replaced with black rectangle

Opening up UEFN to work on our game this morning and all the water has gone - there is an ominous black rectangle in the sky which dissapears when the water zone is toggled. You can only see it from below - viewed from above it blurs the landscape below. Hiding the water zone hides the rectangle, deleting the water bodies and adding new ones does not fix the issue.

Help, this is extremely urgent.

@DubitMike Thank you for your report! We would like to look into this further, would you be able to submit a bug report using the form available here? Fortnite Creative

Submitted, thankyou. We’re doing a revert as time is critical

We’ve reverted to a build we know had water (we have video evidence) and it’s still broken.

@DubitMike as much information as possible here would be great. Can we get screenshots, video, logs etc.?

It’s under NDA - I can’t post them up