When the Automation Lanes are stretched to maximum height the meters default to -0- and stop responding.

By "meters", I gather you mean the envelope value histogram? I can't reproduce this in any case.

Don't know what it's called but it's a vertical slide meter at the right side of the Automation Lane Control Pane with value text at the bottom. When playing it should flow up and down reporting the current envelope value.
 
I just reconfirmed it. After stretching the Automation Lane height past 50% it defaults to 0, and stops responding.
 
This happens in 32 and 64 bit X3e.

I think there's something going on with your particular environment or project. I can't reproduce that in X3e using a volume envelope on an audio track. Both the value and the indicator bar continue to track the changes during playback at all lane heights.

It appears to be a corrupt project as it does work in other projects.