Hose temp

I have a moderate to mild diagnosis for OSA, after the recall I was reissued Dreamstation2 with it was a 15 mm heated tube, my Dreamstation1 had a 22 mm tube initially. Recently when I attempted to turn on my machine it would not come on, I disconnected and reconnected everything and eventually it started to work. I exchanged my previous 22mm hose onto my machine and left the set up off until I got in the bed ( I have the heated tube and always fill my reservoir) once I was ready for bed I noticed my hose was extremely hot, not warm but HOT! the machine itself was normal temp the connector for hose was normal, this scared me so bad. I removed that hose and connected the 15 mm hose that I had been using. I monitored it consistently and after using it for 7:15 hrs last night with an AHI of .7 with no issues I got up turned machine off left it assembled and went to feed my cat came back and hose was extremely warm, I disassembled machine and put up. Any idea why this is happening?