Have you had this issue with other DME? Entirely possible it's simply the way that extractis made.
I've always used LME in the past.
I don't truthfully know the cause. But I suspect its a mix of causes. I have made brews that are pale that were half LME/half DME with no specialty grains (reason was that the DME was wheat, LME was cheaper and I liked the quality but was not available in wheat.) and tasted very good. I made a belgian single this way that was one of my favourite brews.
The factors I believe are the combination of a lack of flavour of the pilsen/golden light DME i used and a low carbonation. I didn't mention but I targeted only about 1.7 vols for the most recent and about the same for the previous one that had an issue.
maybe exacerbated by some mineral imbalance I am not aware of. https://www.homebrewtalk.com/threads/ion-additions-from-briess-pilsner-dme.186443/
I sampled one last night, and was already pretty drunk but it just wasn't that great and still had the issue, 3 weeks in bottle now.
This isn't a brewing-ending issue for me at all, I do about 50% of my beers all-grain, 25% partial mash and 25% all-extract.
Solution for me, barring someone who has had this issue or can explain it is:
1. stop making pale, all-DME brews.
2. switch back to using LME for brews that are supposed to be fairly pale and accept the slight increase in SRM for an overall better flavour.
3. continue using DME in partial-mash brews or ones with strong specialty grain additions ie. a lb of black malt and a 1lb of crystal on top of a DME base.
the reason for me making this thread was to crowdsource a solution or answer and perhaps warn people of a potential issue (though apparently it isnt one for most)