I basically took a 23andme test and found out genetically I was 1% African. The weird part though is that family records shows that my father's mother's grandmother was African, making me 1/16 African. Shouldn't it be closer to 6%?
The science behind "being X % from a certain place" based on genetic analyses is... approximative at best. It relies on the assumption that some genetic traits are only found in certain (narrow) regions of the planet - which for most of them, is not really true.
Additionally, did your test provide any confidence metric for this result? If not, it may mean that it may be derived from a statistically unsignificant number of traits (and the number could therefore mean anything) or maybe it's simply something like 1% with a confidence interval of several points, in which case the result could be a compatibe the mathematical truth. Genomes are large and have complex dynamics, it it probably difficult to get a precise estimate.
On a side note, there is more genetic diversity in native African populations than on any other continent (for reasons pertaining to Homo sapiens history) so "African" does not describe a homogeneous population.
Source: https://www.nature.com/articles/nature13997 doi:10.1038/nature13997