How to View Histogram Pixel Data

What was implicit in the other replies is that the cloud (or cloudy) version of Lightroom that you are showing a screenshot from will not display the percentages under the cursor. It simply cannot do this. It also cannot do a whole bunch of stuff that Classic can do (like print or share images easily on anything but Adobe's cloud) but it does sync all your images to the cloud which some people like. Also not completely explicit was that if you want the interface to be similar to your old Lightroom versions you need to install Lightroom Classic which is the update to what used to be called Lightroom. What is now called Lightroom is a port of the mobile version of Lightroom to the desktop operating system. Adobe made some terribly confusing choices in renaming these separate pieces of software.

The difference you are seeing is between two different applications. The more detailed histogram is from Lightroom Classic (desktop-based) and the other is from Lightroom (cloud-based). Lightroom Classic is more robust and provides more options and information.

There is also a separate Lightroom support forum.

warmly/j

The upper image shows the histogram from Lightroom Classic whereas the lower shows the tone curve from Lightroom.

Theses are two different things, from two different programs, and what you show seems normal behaviour.

Please explain your issue in more details and use screen-captures instead of photos to illustrate the issue if needed.

You appear to be using Lightroom (Cloud Based) instead of Lightroom Classic.  You need to ask your question in the Lightroom forum.  If this is confusing its because of Adobes constantly changing naming conventions.  If you were using a very old version of Lightroom they changed the name to Lightroom Classic and call a different program Lighrroom now.