Zephyr Scale Import intermittently fails and knocks Zephyr Scale offline

I'm encountering an issue where Zephyr Scale Test Case imports from .csv files intermittently fails and globally crashes Zephyr Scale. Has anyone else seen this?

We're not using imports fully yet. I have been performing preliminary import trial runs. I'm making minute variations to the values on the same .csv file with each run. Sometimes, the import completes successfully with the new test case appearing in the list. 

Other times, the import ends with a "Something went wrong" error. Following these occasions, Zephyr Scale has gone offline for all users for a period of about 5-15 minutes. 

I've ceased my trial runs because I don't want to risk knocking the system offline while people are trying to access it - - and I also don't want to risk potentially causing greater harm, behind the scenes.