Missing washer fluid .

Here's a strange one .
Jumped in my A3 3.2 today , turned on the ignition and got a warning light on the dash - low washer fluid .
Strange cos I always top it up every time I wash her , usually only a couple of glugs from a washer fluid top up bottle and its full again .
I popped the bonnet and started to pour in fresh fluid , and poured and poured , it was disappearing as fast as I could lob it in , it didn't seem to be pouring out from under the car though .
I had to take my daughter to school so shut the bonnet and drove off .
The washer icon was still lit on the dash as I parked up at a retail park about 20 mins from home , after dropping my daughter off of course .
When I got back into the car and fired her up the warning light was off , tried the washers , they worked fine , went home and stuffed a hose in the washer tank to see if I could see where it was leaking from but after a bit off gurgling it filled up and held .
I hadn't used the car for a few days before this , only thing I can think of is a joint somewhere that sealed when warmed by the heat from the engine ?
Anyone else had this ?

Cheers ,

Mike .

Sound theory , thanks Pluves1 .

That's true leshkin , I had the premix stuff in so I think it should have been ok .
It must be leaking somewhere because it's still disappearing .
When I fill it up it doesn't empty quickly but most of it is missing after a week or so .
I have been reading up on it , I might be able to gain limited access through the fog light grill ?