Definitely worth sending to www.safe.com/support

The sooner they are aware of these kind of issues, the better.

Please do. In the meantime I'll mention this to the development team and see if they are already aware of it.

I chatted with the developer and yes, it would be great if you could get in touch via the support team. The screenshot isn't enough for us to figure out what or even where the cause might lie. It would also be useful to know if this worked previously in, say 2018. Those formats haven't changed much recently, so I can't tell if it's a new problem or just one that was been hidden up until now.

Thanks, and apologies for any inconvenience it's causing.

This issue occurred in FME 2019 beta versions and should be addressed in the FME 2019 release or later versions of FME.