Why does my refrigerated wine cabinet flood?
My guess is that your fridge (and that really is all a wine cabinet is -- it just keeps your wine at an appropriate temp for wine as opposed to, say, milk) has a "frost-free" feature (most do), it will regularly cycle off to allow frost that has condensed on the coils to melt. There is a small drain in the back of the unit that directs the water into a container where it evaporates (the warmth of the compressor helps that along). The drain is usually tiny (so as not to let the cold air out) so it can plug with lint or debris.
Most of the year, no problem since not that much frost collects on the coils at any one time. Then comes summer and you put off cranking the AC until you are miserable -- now the fridge is running flat out and the air is a lot more humid. When the frost-free cycle kicks on, you end up with a lot of water with nowhere to go. My guess is that soon after, you turn the AC on in your home and things return to normal, until next year.
The fridge coils and the drain are usually way in back and covered. Usually best bet is to pull the unit out and look around the back side of the unit. Since the fridge coils are usually placed at the top of the unit and the compressor somewhere underneath, pretty common for there to be a plastic tube that leads from the drain to the collector cup.