"The JVM was paused for x% of the y seconds at <a timestamp>." This isn't really a very clear way to communicate that the rule has found the largest cluster of garbage collection pauses in this particular recording.

A possible alternative phrasing might be "The JVM detected a cluster of GC pauses for n seconds between <timestamp 1> and <timestamp 2> where Java code execution was paused for y% of the time." but any phrasing that more clearly communicates what the rule actually has detected would do.