Solved by KFrank in post #8 
              
              
                Hi Steve! 
I haven’t worked through this in detail, but a first look suggests that 
the softplus() fix in the recent nightlies addresses your issue. 

Running the script you posted on today’s nightly, 1.9.0.dev20210504, 
seems to show that the issue is gone: 
1.9.0.dev20210504
diffA.abs().max() = te…