One of the early, key innovations for Google's Project Ara modular smartphone appear to have caused the recent delay of the product.

On Tuesday, it was announced that the first Project Ara handsets wouldn't arrive this year as expected, but instead, would be pushed out into 2016. A day later, the Project Ara team tweeted two informational bits that shed more light on exactly what the issue is.

First was this specific tidbit tweeted on Wednesday: "No more electropermanent magnets.#ProjectAra #FailedTheDropTest"

Less than an hour later this follow up tweet from the project team added more data: "We are testing a signature experience to attach/detach modules. #ProjectAra#HopeYouLikeIt."

The most recent delay follows a prior one, since Project Ara devices were first expected in early 2015. The issue sounds like a problem with the various modules when a Project Ara phone is dropped.

Each module fits into a phone chassis like a little block and each has one or more specific purposes.

One block might be the processor while another is the camera and yet another contains memory, storage capacity or a power source.

The idea of Project Ara is to easily swap out components whenever you want to upgrade your handset ,while also reducing electronic waste products.

Based on the team's tweets, it sounds like the block components don't stay attached when the phone is dropped from a certain height. And if they don't stay attached, the phone either won't work at all or will have limited functionality.

That's a shame because the electropermanent magnet approach sounded so promising when I heard about it in 2014. Project Ara modules on the front of the handset were supposed to be held in place with latches, but modules on the back would be held magnetically.

Clearly, based on the team's tweets, that approach isn't going to work reliably so it has another solution in mind or is quickly finding a potential design workaround.