Ok, I have a theory. I don't know what brand products you're using, if you already said so I apologize. When I first got my ostomy no one told me how to sleep or how long my barrier and ring would last. What I learned (the hard way) is that the output of an ileostomy is very different from the output of a colostomy. What comes out of the small bowel is very acidic and does very bad things to yours skin if it touches it, and breaks down barrier rings fairly quickly. How quickly obviously depends on the person. The output of a colostomy is basically like regular folks' poop. It can get on your skin and not bother it much, as the acids have been re-absorbed by the colon.
I found if I wore my barrier too long it would turn into a white-ish goo, and stop sealing very well. And for me, being high output, too long was more than 2 days. The same thing happened if I flushed my bag with water to clean in out every time I dumped my bag. It would cause the ring to degrade rapidly. I know others on here flush their bags regularly and don't see what I saw.......and I say good for them. But for me that simply wasn't the case.
Another no-no is sleeping on your back if you're an ileostomate. Because when you have output it will simply pool around your stoma and attack your barrier ring and/or barrier if you don't use a ring. Laying on your side is better, assuming you have enough space in your bag for your putput when you bag is horizontal and not vertical. Otherwise the same thing happens......your output stays around your stoma. The best way to sleep.........at least for me......is on my stomach with my right knee brought up. That puts a space under my bag and my output drains down and away from my stoma. When you said "whitish" I was thinking more along the lines of a fungus, not of barrier turned to goop.......but that is whitish too. And it's glue-like.
So I'm betting what you're experiencing is your barrier disintegrating from being in contact with your output. There's a pretty easy way to tell. Empty your bag into a plastic cup and then toss a new barrier ring in there and start the clock. See how long it takes to get gooey and gluey. If that lines up with your change interval.......you may have found the problem. Let us know what you find.