Sagemaker Processing Job does not terminate itself

Hello,

I am trying to do some simple preprocessing to my data, to be specific, I am trying to split my data into train, test and validation set. I want to make use of the processing job feature and have written a script for it.

However, when I executed the code to create a processor and run it, it says it is creating the processing script and continues running for more than 20mins, even though I only have 1400 examples in my dataset. I had to manually stop it and when I check the cloud logs, the last line of the preprocessing script is already executed, meaning the script ran properly and completely. The output can also be found in the s3 bucket. So my question is, why my processing job is not terminated automatically?