If there is an allocation failure during concurrent remembered set scanning, GC needs to wait for concurrent remembered set scanning to complete before it can degenerate. Depending on the size of old-gen memory and heap regions and the density of interesting pointers, this can take several seconds.

The delay in cancellation of remembered set scanning delays the time at which the subsequent stop-the-world pause for degenerated or full gc ends. This increases the number of transactions that are impacted and increases the degree to which each of those transactions is considered to be late.