I was in a similar situation as both ELM as well as the ESM appliances have this defect.As a workaround I used the normal cage nut with the screw cap and luckily it was a proper fit for this.But to do that I had to remove both the appliances from the rack before I could place the cagenut in the rack .
Thank you for information. So I know I have to prepare cage nut before hardware installation.
IMHO, hardware design defect likes this one can not get fixed soon. We might have to wait for a few years...