Unable to draw bounding boxes in deepstream using a multi-task classifier model

Yes, if you model needs prepross or postprocess, you should add the function to process it. Maybe you can refer the topic below:
https://forums.developer.nvidia.com/t/getting-0-0-0-0-output-from-tao-multitask-classifier/210302
Also, you can add your model training process step by step.
At last, There may be some problems about the order of the output layer. You can check it.
In your log:

INFO: [Implicit Engine Info]: layers num: 4
0   INPUT  kFLOAT input_1         3x80x60         
1   OUTPUT kFLOAT pose/Softmax    5x1x1           
2   OUTPUT kFLOAT object/Softmax  2x1x1           
3   OUTPUT kFLOAT action/Softmax  6x1x1    

But in your config file:

output-blob-names=action/Softmax;object/Softmax;pose/Softmax