I have the same problem.
Origin, Blizzard works totally fine but Steam wont.
Have to download a game like 4-5 times until it is fully cashed.
Also SteamCache Monolithic crashes at about 50% of the download.
When SteamCache crashes the error log shows something like:
I think that is causing my cache to crash but not that I have to download a game multiple times until its fully cached.
Any help is appreciated