The workaround was from Dec 29, 2017. The fix in the same thread was Jun 30, 2018.
Are you saying that 2.0.4.5 has been tested and shows the --blocksize problem again?
What’s more concerning is that if –dblock-size must be given, how do you give it if backup has several?
Choosing sizes in Duplicati says that (unlike –blocksize) it can be changed at will for an existing backup:
Unlike the chunk size described above, it can be beneficial to both increase or decrease the volume size to fit your connection characteristics. Also, the volume size can be changed after a backup has been created.
A quick search of known recent issues didn’t find this, but if well-proven then maybe you should file one.