Tense Inconsistency (Past Simple and Present Perfect) or wrong Sequence of Tenses (Present tense follows Past tense)?

In the following sentence, the Present Perfect in the second clause sounds a little off to me, yet I cannot put my finger on WHY that is.

During this time (Subord. Clause 1), I was able to gain/ I gained many new experiences (Independent Clause 1), and although I enjoyed it (Subord. Clause 2), my lifetime dream has always been to become a teacher (Independent Clause 2).

-> the reason the Present Perfect was used here, is because it is still true in the present. It has been and it still is now the person's dream to become a teacher.

It is clearly a sentence which contains two independent clauses and two subordinate clauses (Please, correct me if I'm wrong!)

My two solutions to solve this problem would be:

  1. MAKING TWO SEPARATE SENTENCES

During this time, I was able to gain/ I gained many new experiences which I really enjoyed. However, my lifetime dream has always been to become a teacher, which is why I’ve decided to start my current studies in…

OR

  1. CHANGING THE VERB TENSE in the second subordinate clause to PRESENT PERFECT (to not interrupt the logical sequence of the tenses)

During this time, I was able to gain/ I gained many new experiences, and although I’ve enjoyed it (referring to this time), my lifetime dream has always been to become a teacher.

My question is - WHAT IS THE EXPLANATION as to why the original sentence isn't correct? How do I explain this to my student?

Is it TENSE INCONSISTENCY? Do we have to keep the same tense throughout a clause which is why it's better to rather have two separate sentences instead? Or is it a problem with the logical SEQUENCE OF THE TENSES, which is why the Present Perfect should be followed by the Present Perfect ?

Thank you in advance! :-)


Without changing too many details, I came up with this.

During this time, I gained [amazing] new experiences and although it was an enjoyable period, it has always been my lifetime dream to be a teacher.

The Simple Past is used in the first two clauses because it refers to a specific and completed period of time. However, seeing as the speaker's ambition is ongoing, the Present Perfect is suitable. There is no rule that I know of that says you cannot have different tenses in the same sentence, e.g.

“She used to teach children at a nursery school, but today she works as a software engineer.”