Yeah, I've been working with BLE now for clients for 3 years, it seems like most people think of their devices as little CRUD servers (unless you're doing genuine pairing with constant data streams). BLE would be much better using a simple REST model than the GATT table model.
> Also, the bluetooth library in Android started out terrible and didn't improve despite being replaced
One thing I'll give Apple credit for is having a very solid bluetooth stack. We've had only a handful of BLE connection failures on our testers apples devices over the past 3 years, whereas on android test devices we get at least one connection failure DAILY that interrupts test cases from running. Furthermore Android devices just reach a point of critical failure where you need to just restart the device to resume BLE.
Additionally, remote controls for cranes, concrete pumps and other machinery may be the cause, depending on the frequency bands these use. Here in Germany, it's all 433/869 MHz from what I remember from sites I worked at, but no idea about the US.
PS I am in northern Europe, not the US.
Edit: Yes, they do exist - you can google this. But on reflection, a commenter below is probably right that it's more likely wireless security cameras, given typical site requirements (range, penetration depth)
The one thing nobody seems to do is stick to the standards provided, because they simply aren't broad enough for the creative stuff that people do with Bluetooth and Bluetooth LE. Most of us working in this space have some cack-handed way to advertise data without connecting because (for example) most of the connections to Bluetooth LE devices involve you having to do device discovery, even if you are connecting to 500 of the same damn device.
Also, the bluetooth library in Android started out terrible and didn't improve despite being replaced, the Bluetooth chips in most cheap phones are also rubbish and fail when you exceed their undocumented number of connections, often requiring a reboot of the device etc.
In short: You can sheet a lot of the problems back to an ill thought out spec and bluetooth chips in things like phones that just plain suck.
Things like RF interference - I just don't know. Sometimes there is just a heap more bluetooth traffic around than anybody knows about. Packet sniffers are relatively cheap, it's interesting to fire one up in a busy office and see how many bluetooth packet collisions there are (hint: it's a lot). Blame RF storms or whatever but it's more likely to be something advertising a lot and spamming the spectrum.