Hi JGA, as discussed in an email I found that it appears to be related to how the blocks are defined in this case causing issues on the import. In particular, there is a rotation applied to the blocks (14.3) in most cases.
I have opened an issue internally to look at this.
A workaround for this (though not ideal) would be in Acad explode all blocks and make a block out of everything, then it will import correctly. Not sure why but that made it work.
If you want to preserve blocks I have also found that if I rotate everything from the origin, so that it is parallel to the UCS, then select all blocks and reset the rotation on them to 0, select everything and put it in a block. I do notice that any block that was mirrored (toilets for example) will need to be flipped correctly in cad as well.
Thanks for bringing this to our attention
Trent