I have received a tank of the new castable resin with a problem in the rubber valve that release the resin, mine have a cut marked but this cut is not done. I was afraid to cut it myself but i though about the old tank, i check that they were the same, pull it from the old tank and I have cleaned it with IPA, pulled the new one and push the old one after I rinsed it with clean IPA.
Now it is working. I hope that this will be of help to someone