How come mining elements sometimes yields no resources?

There doesn't seem to be any reason for it, and this turns particularly annoying when mining Iridium for example since those formations are already incredibly small to begin with.

One way to minimize wasted time is to use the scanner. If it highlights the resource with those transparent cubes then you can still collect resources at that location. If there are no cubes then you can still dig there but will receive no resources.

There's a bug where mining the edge of a resource makes the ground adjacent to it change to look like that resource. Watch the edges as you mine, and you'll see the emeril (or whatever) "spread" across the ground as destroy the edge of it. You don't receive any resources when you mine it, because it's just ground that looks funny.

To easily tell what is actually a resource and what is ground that's glitched, use your scanner. Resources will show up with a matrix overlay, and the ground will not.