**No, I did not push the stopper into the carboy.**

I bought some new stoppers a couple months ago. I don't remember who I purchased from but they are the tan, size #10, Vintage Shop brand. I noticed a lot of rubber aroma when I opened the package but didn't think too much of it. However, I have detected a rubber aroma in my first 3 beers made with these stoppers. Fermentation issues or autolysis, right?
Skeptical of the stopper being to blame, I submerged one in a tupperware container of RO water and sealed it, with another container of just water beside it. 24 hours later I can smell the stopper as soon as I open the container even though it is completely submerged, and there is a strong bitter/rubber flavor in the water. I can still taste it 20 minutes later.
We've all read multiple posts of people who DID push their stopper into the carboy, and the responses usually say "you won't be able to detect it" or something to that effect.
So my question is: What is wrong with this stopper? Just a bad batch? Has anyone else experienced this, and if so did it go away over time or did you do anything to de-gas them?
I have now put one of the stoppers on an Erlenmeyer flask of water and I'm betting in a couple weeks I'll at least be able to smell them in the water.
I'm not using them any more either way, but any thoughts?
cheers--
--Michael