--throttle-upload affects restore download performance #3272 is the open issue which seems to be suspecting a parameters-are-backwards problem, but is hung up in some confusion. One reason is that throttle code does Read and Write, so how that translates to upload and download might not be obvious.
Hash mismatch download corruption, likely from throttle buffer offset being reused #3782 covers a Write bug corrupting download. My B2 test seemed to be doing OK but OneDrive had issues. I suppose YMMV.
The defect itself is real old, but appears subtle enough that conditions must be right for it to cause issues.
Fix implementation of ThrottledStream.Write #3811 didn’t catch v2.0.4.22-2.0.4.22_canary_2019-06-30 so will presumably be out in whatever next canary is, and I hope that it can then flow into beta. Plan unknown, however since you’re already on 2.0.4.22, you might be the best person to try next canary to see if fix fixes.