Asynchronous SLSBs are leaked if they execute too quickly

I have created a SLSB which exports a single asynchronous service, and a singleton bean which invokes it via a TimerService. Once every minute, the singleton executes the SLSB 15 times via a loop. If the asynchronous service executes "too quickly" (e.g. 500ms or less) then the asynchronous thread is destroyed and the SLSB is leaked, along with all of its resources. Over time, these SLSB instances force an OutOfMemory exception.

However, if the asynchronous service is "slow enough" then the asynchronous thread stays in the pool and the SLSB can be reused. This is the behaviour that I want, although I would obviously still want the service to execute as quickly as possible.