No, rejection of "little" in this context isn't a computer glitch.
In English, small and little can be used as adjectives, but they are not always interchangeable. It depends on the context, the nuances.
To describe the dimension or size of a building in a factual way, use "small":
- The school is small.
- The house is small.
To describe the stature of an object in a pleasant/cute way, use "little". It works better with "house" or "church":
- I want to retire to a nice little house by the ocean.
- They got married in a little church on a hill overlooking the valley.
When "little" describes a person or animal, it can mean "young". For example:
- Julie is a little girl
- Mary had a little lamb
There are tutorials on the internet about the differences between words with similar meanings: little small; small tiny; big large; big huge; tall high; long tall
the use of the in this sentence is only allowed in a context
Similarly with die Schulen in German.
It presupposes a context where the speaker is talking about a specific group of schools (e.g. all the schools in a particular area) and the listener can identify that group.