An error in the sentence's tense

[Omneya Shakeep]

Is an error in the sentence's tense considered an objective or subjective error?

For example:
What I disliked the most was that there are parts where the writing is hard to understand.

Is this sentence correct? Or should the verbs (are) & (is) be in the past tense?
If it is incorrect, is this considered an objective or subjective error?

[Elavarasi Charles]

Hi Omneya!
In my opinion, it is objective error. In your given example 'was' is the acting verb. As in, it determines the tense of your entire sentence. It means everything that comes after it must be in agreement with it too. It might seem correct to argue that the phrase 'there are parts where the writing is hard to understand' is a fact that continues even in the present. In that case, your sentence should be,

'What I dislike the most is that there are parts where the writing is hard to understand.'

You can also use (disliked) in the above sentence. But it might not answer whether or not you like it in the present moment seeing that the writing is still hard to understand. The problem is in present means the reaction must be in the present too.
Hope this helps.

[Omneya Shakeep]

Thanks for the clarification.