Ableton Forum

Can you provide some more specifics about the issue?

In Session or Arrangement?
In Arrangement it will create a new clip, but in Session it overwrite the currently selected clip. Nothing's changed.

Sometimes, for an unknown reason (at least to me), Capture would simply not work, like it didn't care that you actually played something.
But it doesn't seem to be what you are describing, and your description is actually in par with how Capture work.