I brewed a hoppy red that I just dry hopped. I took a sample while the fermenter was open and while the aroma was great along with the initial sip there was then a astringency that lingered. Is there any cure but allowing time for it to fade? I believe the culprit was due to the steeping grains if this helps.
I doubt your steeping grains are the issue unless you really over rinsed them and even then I would still have my doubts. Leave it alone and let it do it's thing. If you still have a problem in a month then try to diagnose it.
Perhaps it's just the "green" beer flavor. One of my recent batches had what I thought was a slight astringency which caused me to review my mash/sparge technique, but after a month or two I don't notice it any more.