bugs – Wrong result with symbolic calculation in Mathematica

I am looking at the expansion of a time series
Series ($left(sum_{s=1}^inftyfrac{r}{(1+k)^s}x^{s+1}right)^{-1}${x, 0, 2} and I get a result like

1 + (r x^2)/(1 + k) + SeriesData(x, 0, {}, 0, 3, 1)

If I now simplify the above term first, I get $frac{1}{1-frac{x^2 r}{1+k-x}}$. Running the Series-command on the invers of this term, i.e., Series(1-(x^2 r)/(1 + k - x) gives me a different answer then the one above. This seems to be a bug or am I making a mistake here?
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