To repro this:
1. Open the attached project ("BugReporter-TouchTimeline.zip")
2. Open the SampleScene
3. Make sure "Touch Simulation" script component on 'Global' GameObject is enabled
4. Enter Play Mode
5. Click and hold the left-mouse button on the Game View window and drag it outside of it
6. Notice "Pointer should have exited all objects before being removed" error in the console
7. Exit and enter the Play Mode again

Expected result: No errors are thrown
Actual result: 'A Native Collection has not been disposed, resulting in a memory leak. Enable Full StackTraces to get more details.' error is thrown

Reproducible with: 2019.3.10f1, 2020.1.0b5, 2020.2.0a7
Couldn't test with: 2017.4, 2018.4 (minimal required package version is not supported)
Reproducible with package versions: 0.9.0-preview, 1.0.0-preview.6

Note: Error is also sometimes thrown after entering the Play Mode when Enchanted Touch API is used (usually after 'Pointer should have exited all objects before being removed' error is thrown in Play Mode)