Why is Sequencer causing Random Freezes?

We’ve run into a problem since upgrading to 4.17 with a sertain project. I was unable to reproduce the issue in a clean project.

Issue Details: After upgrading to 4.17 the level sequence in one of our levels causes the engine to freeze, forcing us to end the process forcefully with task manager (windows 10 x64). This only happens when we have the sequence editor open (the sequence playes fine when the game is running), in perticular it seems that the scrollbar at the bottom of the timeline in the sequence editor almost always cause a crash when we click on it.

Issue Backround: We made a VR presentation with a sequence in UE 4.15. We were unable to package because of some issue in 4.15, upgraded to 4.17.2, this fixed the packaging problem but since then we have the freezing problem when the sequence editor is open

Thanks for any feedback or advice.