In 1.7.19 we observed a memory leak after SubstituteLogger was returned during initialization.

It appears that in some case, the eventQueue is not drained correctly and/or the substituted logger is not replaced with the delegate correctly. The result is that use of the logger will leak memory and eventually OOM. In our case we had servers that started up OK but after a few days of logging the eventQueue object reached 1GB in size.

I am attempting to find the issue using a debugger and breakpoints, because this sort of problem is hard to express in a unit test. However, so far I have been unsuccessful. Unfortunately I cannot provide a heap dump for this issue since it would contain private customer information, but I'm happy to provide snippets or screenshots if it helps.

I also notice that there is a 1.7.20 release available now; but it does not appear that the single issue addressed in that release is relevant here.