I use nasal pillows but was still having problems with the air blowing out my mouth. I tape my mouth firmly and it would still break the seal.
I suspected my throat was getting pinched from my pillow (chin getting closer to chest) so I tried sleeping with no pillow which should keep your airway more aligned. Whoa! Last night I slept the entire night without getting woken up from air to mouth issues.
Is all this expected?