Why is glycerine doing this to my slime?

I bought some glycerin from Amazon to try to revive some old slimes and be better about slime upkeep. I've tried it on two old slimes and something strange has happened with both. The first one was a snow butter slime from wiener dog slimes and the second one was I believe a cloud cream of some sort from Sonria slimes. Both of them were over a year old and had shrunken to half their size. When I first added the glycerin, it seemed to help them become stretchier again (they were both really stiff). I added a decent amount to both. After sitting over night, the slime expanded a bunch but seemed to almost turn to clay? It no longer stretched at all like slime and was just kind of a squishy ball. I used citric acid to melt it back down and then reactivate it but it seems its stuck in this squishy ball state - nothing like slime. Did the glycerin rehydrate the clay too much and there wasn't enough glue left for it to be slime? Am I using glycerin wrong?

Any advice about how I should/shouldn't be using glycerin in my slime is greatly appreciated!