Word meaning the outcome is different to that intended

A friend has said that there is a word meaning the outcome is something very different from that originally envisaged. For example:

The Australian government introduced a "First time home owner" bonus. Where if you were buying your first house you would get a lump sum cash. Of course everyone selling a house in that price backet put the price up by the same amount as the lump sum and first time buyers didn't benefit at all.

Does anyone know if there is a word meaning this and what it is?

The usual term for this is unintended consequences. I'm not aware of a single-word term for the general case, although there are some examples for specific contexts – for example, serendipity for unintended discoveries and side-effects for unintended complications.

Dictionary.com lists this meaning as one sense of anomaly:

a·nom·a·ly Noun

Something that deviates from what is standard, normal, or expected.

However, the first sense /two senses (standard; normal) here is / are far more common (though deviations from the normal are often unexpected).

The adjectives unexpected and unforeseen would normally be applied in this set of circumstances, but do not have noun counterparts. Unintended applies, of course, when the (probably - depends on the degree of risk considered acceptable) unexpected outcome is triggered by a human intervention such as the introducton of a "First time home owner bonus".