Always found vs. always finds

Test No. [color=blue]errors/inter-15 “Sleep well”, question 1

She was always finding it difficult to get up in the morning.

(a) was always finding
(b) to
© in

Test No. [color=blue]errors/inter-15 “Sleep well”, answer 1

She always found it difficult to get up in the morning.

Correct entry: always found
The error was: (a) was always finding

You have [color=green]found the error but your entry is [color=red]incorrect.
She always finds it difficult to get up in the morning.
[size=200]_________________________[/size]

couldn’t it be in present tense, if not why?

What you have written is grammatically correct but in this context the whole story is told in the past and so in this sentence for consistency you also need the past form.