Thank you for your reply.
The backbone of ASPP is a V-Net, and the output of its final decoder layer is fed into the ASPP module. I call the input to ASPP up4, and it has shape (32, 144, 144, 144).
It’s strange that I tried the following operations and they also worked:

Take the feature map above up4, i.e. up3 with shape (64, 144, 144, 144), use its first 32 channels as ASPP input;
Take up4's symmetric feature map of the V-Net, down1, as ASPP input.
Save up4 of the main model, and feed it into my simple toy model;
But if I change the data batch (random shuffle), the problem remains.

I cannot understand the error message, so to be honest, after those tests, I don’t know whether it’s a bug or it’s my bad 
I am gonna work on it to see if it can be reproduced in a minimal code snippet.
Again, thank you, prtblck!