A cider with EC1118 yeast could easily finish at .990.
So, you bottled a cider before it was finished, and added priming sugar. It sounds like a sure recipe for bottle bombs. I'd open the bottles and get them in a carboy ASAP and let them ferment out.
Cider isn't beer- three weeks is NOTHING. If it wasn't done fermenting, it wasn't done, and a yeasty taste may or may not mean anything.
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