Correctness of omitting a definite article or a preposition

I am writing an essay about my university experiences and a suggested correction from an English Ph.D. sounds wrong to me.

The suggestion is

In our meeting to discuss the spring semester of my junior year, my adviser set forth a challenge.

She made a similar correction later,

One graduate course had been sufficient to consume my time in the fall semester.

As a native English speaker, both of these corrections sound like grammatical errors to me, but I do not have the linguistic knowledge to articulate exactly what, if anything, makes them incorrect. (I spend much more time on math.se than english.se!)

Are her suggestions correct?

Solution 1:

Time periods can be used without articles. A different example:

One graduate course had been sufficient to consume my time last semester.

I personally find it awkward to use "fall semester" instead of "last semester" but it's the same basic idea.

Solution 2:

I think the corrections are technically correct, but they make the sentences awkward. Perhaps you could reach a compromise, such as:

In our meeting to discuss my junior year (plan), my adviser set forth a spring semester challenge.

and

One graduate course was sufficient to consume my fall semester.