I've found threads describing similar problems with answers stating that these are bugs that should be fixed with newer version of the npm package but I was able to replicate the behavior with current version 16.4.54.
POPrince Oliver Syncfusion Team February 28, 2019 05:09 AM
Thank you for contacting Syncfusion support.
We have validated the reported issue and we are considering this as a defect in our EJ2 DropDownList control. The fix for the reported issue will be included in our upcoming 2019 Volume 1 main release which is scheduled to be rolled on March 2019. Meanwhile you can now track the current status of your request, review the proposed resolution timeline, and contact us for any further inquiries through this link: https://www.syncfusion.com/feedback/4979/
PRPhilip RoelofsMarch 1, 2019 04:32 AM
thank you for your feedback.
I'm happy to hear that this bug will get fixed soon. I'm looking forward to next release.
POPrince Oliver Syncfusion Team March 4, 2019 12:14 AM
Most Welcome. We are glad to help you.
POPrince Oliver Syncfusion Team April 17, 2019 12:55 AM
SPSureshkumar P Syncfusion Team June 15, 2020 06:13 AM
Thanks for your update.
Based on your shared information, we have created the sample and could not replicate the issue from our end. please find the sample below with version 17.4.43. if still you have facing the issue, then please revert us with issue replicate sample with detailed issue replication procedure that will help us to provide exact solution as earlier as possible.