Many of these studies don't account for test/retest reliability of IQ tests. Height is pretty easy and reliable to measure, and it doesn't change based on how much sleep you had the night before, or whether you ate breakfast, what the conditions of the test were, the time of day, etc.

The test-retest correlation on most IQ tests is around 0.7-0.8, whereas for height, it's almost 1.0. That means if you're measuring intelligence by a single IQ test, the correlation with genetics has a maximum of 0.7-0.8 due to noise in the test.

Studies that either explicitly correct for this, or look at averages of multiple tests taken over time show higher correlations between genetics and intelligence.