It is common for carpenters to kerf a wood stud to remove a bow in the stud to allow for the wall finish to be flat. Depending on the function of the wall, such as load bearing, the kerf in the stud may be reinforced with a section of 2x material lapped and fastened to the full height stud. Regardless of how the stud is kerfed, reinforced, etc. the most important piece of knowledge involved is the function of the stud. Knowing what the stud supports can result in an appropriate repair solution.
These 2x6 studs have a kerf that leaves just over an inch of solid material.
Now, back to that forest and tree stuff. The worker who cut these studs could only see the bowed stud (tree) in front of him. Had he looked at the big picture (forest), he might have realized that kerfing a first floor stud in a four story building might not be a good idea. And yes, this wall does carry floor trusses from each floor above.