This has never happened to me before! Last night I made Refrigerator Pickles using cucumbers and an ordinary vinegar, water, sugar brine. My intention was to make a couple jars for co-workers who would use them within a few weeks.
I sterilized my jars, lids, and rings but didn't keep the jars hot. The brine simmered but never boiled and was allowed to cool down quite a bit (not completely cool to room temperature and still warm). I filled the jar with my vegetables and added the warmish brine. Then I added hot lids (I was simultaneously actually canning apple butter so they were simmering), sealed with rings, and set aside to cool. Within just a few minutes I heard the lovely popping sound all canners long for!
I don't trust it for long term storage since I didn't go through the actual entire canning process. Once the jars cooled to room temperature, I put them in the refrigerator; this morning, I tested the lids and they are in fact sealed. Are they safe for long-term refrigerator storage? I've had trouble in my early attempts at getting a jar to seal but never had a batch seal on me unintended! :)