Simplus cushion not inflating

I use a Simplus FFM, and I've had good results the past couple years. I received some new cushions from Lincare this week and am having trouble with them inflating/sealing properly.

I opened one cushion and have used that though something wasn't right. Today I realized that there was something about the cushion that wasn't behaving right. It would seem like it was inflating properly but then was caving in. I kept adjusting the mask but couldn't resolve that. I opened a different cushion to compare and had the same problem.

What can I do to troubleshoot and/or fix this? I haven't had this problem with the Simplus before.

I have recently started using the Simplus...I found no problem with inflating. Previously I used the Quattro. I have been switching between the masks. Have you checked the cushion itself for a small leak?

If it isn't inflating that's a sign that there's a leak somewhere. Try repositioning the mask and if that doesn't solve the problem then replace the cushion.