A few comments/questions:
As you noted this is urgent, have you put a support ticket in with ESRI?
I can import a feature dataset into the sane geodatabase. I can say that with testing Postgres and Oracle, they also exhibit the same problem.
Importing into a FGDB works. If I export the raster from the FGDB to the Enterprise Geodatabase, that also works
I was able to locate the file you are trying to use at QGIS-Training-Data/exercise_data/raster at master · qgis/QGIS-Training-Data · GitHub. I was also able to import this to a SDE database running on SQL Server 2017 using the following method as a workaround since Raster to Geodatabase is not working for you.
1) from ArcCatalog, right click on the SDE database Connection and select New>Raster Dataset
2) in the Create Raster Dataset dialog
3) Again in ArcGIS Catalog, right click on the new Raster Dataset you just created and select Load>Load Data
4) in the Load data dialog
This will create a mosaic Raster Dataset for you on your SDE database
Thank you for the response.
In previous versions of Arc I could just import that raster dataset as is without any problems. I did not have to do all the steps you did.
I tested this on 10.6.1 a while back, and if you have an Enterprise GDB, you can use Desktop to import the raster dataset as is, without doing your steps (Have to check this though, as I have reverted to 10.5.1) The last time I checked I was also pretty sure you also could not create mosaic datasets as well. I will install 10.6.1 later and check.
It just feels to me that there was a functionality change to 10.6.1...
So in short, I have just been trying to import a raster dataset (tiff file) into an Enterprise Geodatabase just like in previous versions. (Raster to Geodatabase tool) (Not raster catalog)
You may want to revisit Asrujit SenGupta's earlier post pertaining to the 10.6.1 Raster Patch. I was setting up a new virtual ArcGIS Desktop 10.6.1 this morning and ran the Raster_to_Geodatabase tool before installing the 10.6.1 Raster Patch. I received the same errors you have reported with the files from the QGIS Training Data. After running the 10.6.1 Raster Patch the Raster to Geodatabase tool ran without issue using the same files.
Make sure you do not have any apps open when running the Patch or better yet run the Patch immediately after a restart as an Administrator.