Upgrading 5.10.4 to 5.10.5 cause test run to hang

Problem

*Do you want to request a feature or report a bug? Might be a bug What is the current behavior? Update: I think I managed to drill down a little but still not quite sure. I isolated to a few more specific test case suite. Will update here once I have more findings. Update: Sorry, wasn't able to find anything conclusive yet.. --- When using `5.10.4`, when I ran my test (ts-mocha), it run smoothly as usual without any issue but once I upgrade to `5.10.5`, there seem to have some weird issue like "hanging" on the test case. I don't have any error, or anything. Based on the changelog, the only thing it seem to possibly affect is the upgrade of `mongodb driver` to 3.6.2 but I am not sure where to begin checking. I'm not sure if it has anything to do with #9203 ? Just a wild guess. I am still able to run my application without issue, it seem to be affecting the test run now All test case seem to hit the `timeout` limit of 10s I understand this is little to go with, but do let me know what I can do to provide more information What is the expected behavior? Test to run as per usual to what it does in 5.10.4 or before What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version. Working node: v12.18.4 mongoose: 5.10.4 mongodb: 4.2.0 Not working* node: v12.18.4 mongoose: 5.10.5 mongodb: 4.2.0