Megane RS 265 head gasket

Hi guys,
One day coming off the freeway I noticed my temp gauge fluctuating up and down and when I got home noticed a lot of steam out the exhaust. Code read cylinder 3 misfire, removed the sparkplug and water shot out the cylinder. Thought the head gasket was blown and parked the car. Bought the car recently and only had water in the system not coolant.. Anyway the water was low and there was also gunk in the walls of the reservoir, oil/greese. No water was mixed with oil on dipstick. I pulled the head off and the head gasket is fine and no signs of head/block issues, head bolts were also tight. Havnt had the head pressure tested yet, but does anyone else know what the issue could be? Could the turbo be pushing water into the intake? Motor has done 80, 000 km stock and looks in decent shape.
Thanks, any advice would be greatly appreciated