I'm not familiar with that drain, but a quick look at their site makes me wonder about an improper install. It sounds like the drain was just set onto the fresh mortar without consideration to the directions (or maybe something wasn't lining up after it was installed), and then it wouldn't stay put afterward so they siliconed it in place. Call the mfr to get more info. I would consider a repair by chipping out the adjacent tiles, removing the drain top, etc. and reinstalling a new one. (Don't mess with the drain flange underneath!) If it's similar to a Schluter drain, it's a bit of a pain but it can be done. Again, call the mfr to get more details. Good luck.

Here is a link that might be useful: Ebbe

homebound - Thanks for your comments. I had also x-posted on the bathroom forum and received some responses. I called the mfg and sent him pics. Ebbe drains is sending me a remover and two new construction plugs in case the grate needs to be reset. The tile installer has called me back and told me that he will do whatever it takes to complete the job to our satisfaction. I really think the tile installer just did not understand how to set the grate for easy removal.

Good news. I removed both grates with the remover kit from Ebbe and sent them pics of the installation in both showers. They advised that it appeared they were installed properly but just caulked and siliconed into place. I went over their instructions with our tile installer, who cleaned up the grate and fitted it into the plate without silicone. It fits perfectly and has no screws. I sent final pics to Ebbe and they agreed that everything appeared to be properly fitted.

Thanks for the update. That is good news.

I am installing a new corian shower pan. The plumber thinks the Oatley shower drain will leak. It fits over a 2 inch cast iron pipe with just a ribbed rubber gasket. Shouldn't there be a clamp or solvent to hold into place? Has anyone installed this type of drain?