I am currently enrolled in construction classes. Can anyone answer this question?

Why is it that some wall studs can't be installed at the ends of a wall or at only one end of a wall?

Could it have to do with... load bearing vs non-load bearing studs.

Yes? But what would fill that stud void?

Load bearing vs non-load bearing studs, What would fill that void at the end wall?

Sorry, I do not understand your question.

An end wall will usually have or attach to a corner.
Or
The end of a wall section could attach to the interior of another wall forming what may be called a T section.

When building a wall with two or more sections and using top and bottom plates that are 8,12, or 16 foot long, the last stud is centered on the very end of the plate.
Let's say you are building a 20 foot wall using 12 and 8 foot plates. The last stud will be half on the first plate and half on the second plate.

You can leave it off the first section, then put the first stud of the second section centered on the very beginning of the second plate. Or, you you can do it the other way around. Put the last stud centered on the very end of the first plate and put the first stud of the next section centered 16" from the beginning of the second plate.