Just some context so people understand this better: This is not an indication of some "back to coal" trend.
Wind has overtaken coal for the first time last year. Now for a few months the situation is back to coal as the most important source. These things obviously fluctuate and thus it's not a linear trend, but the overall trend is still that renewables are growing and coal is in decline.
(And to be sure I'm not misunderstood: That doesn't change the fact that the high coal use in Germany is a big problem and the wind buildout is far too slow.)
Wind has overtaken coal for the first time last year. Now for a few months the situation is back to coal as the most important source. These things obviously fluctuate and thus it's not a linear trend, but the overall trend is still that renewables are growing and coal is in decline.
(And to be sure I'm not misunderstood: That doesn't change the fact that the high coal use in Germany is a big problem and the wind buildout is far too slow.)