RemstarAuto A-Flex M Series Rain-Out

I'm trying to help an elderly friend who's mask is suddenly filling with water. I've checked the water chamber it is not over filled. I have changed the humidifier with an old one she had for the same machine and it is still leaking. Is there a baffle somewhere that might be missing? She has used the machine for several years and not had this problem before. The machine has always been in the same location so I am sure that is not the issue. Can you help? She is getting ill from all the water she is breathing in during the night.

What mask is she using?
Has the temperature in the bedroom changed...lower maybe?
If the condensation is in the mask and not in the hose it could be from the moisture in her own exhaled breath that is condensing.

Some things to try.
Make sure machine is a bit lower than the mattress as this will allow gravity to help route any condensation down the hose and into the humidifier water holding tank.
Warm up the air in the hose to help prevent condensation in the first place...hose cozy or some sort of insulation around the hose to help the air in the hose from cooling down and releasing the water...remember warm air can hold more moisture than cooler air.
There is a stand alone heated hose that might help...the Hybernite 2300. Warms the air in the hose. There's also a reptile heater cable adaption that can be done to help warm the air in the hose.
Increase bedroom temperature to help reduce the cooling off of the air in the hose.

If the condensation is mainly in the mask itself..then sometimes we have to help insulate the mask..depends on which mask is used.

She is using a mirage mask. However this just started happening the past couple of days. Nothing has changed. She is due for a new machine but cant get in until next month. Is there a baffle between the humidifier and the machine that might be damaged?

No baffle that I am aware of. I used to use a M series machine.
You might also try turning the setting down. Maybe it is generating a higher heat and thus adding more water to the air so that increases the chances of condensation.
There's really no way for the water in the holding tank to get blown into the hose and certainly not blown clear up the hose into the mask.
The moisture at the mask level has to be from condensation.