Steps to reproduce

1. Item starts a custom script:

[ITEM.PNG]

2. The script outputs some values that are used by a dependent LLD rule which creates some calculated items.

[prototypes.png]

3. New host items all have a simple "Discard unchanged" preprocessing step.

[preprocessing.png]

4. Despite the preprocess step, repeated values are occasionally being saved to the database.

[values.png]

Expected:

It was expected that only different values were collected.