Memory overhead not shown in ESXi 6.0 - Known bug?

Hi,

I just realized that memory overhead in all my VM's hosted inside an ESXi 6.0.0.3568940 (ESXi 6.0 U1b Express Patch 5) is not shown.  I mean when I inspect every VM via vSphere client, in the Summary tab, the field Memory overhead is empty as shown below:

My vSphere Client is 6.0.0.3562874.

I have other ESXi (4.1 U1, 4.1 U2 and 5.5 U2) and they don't have this problem.

Is this a known problem?

Thanks