There is a bug in SST script. It generates random key and put in to
But when SST script does backup it encloses $transition_key variable in single quotes
Here is example from SST trace log
Single quotes do not interpolate anything, get variable literal value (and lose its meaning). So transition key always equal to string "$transition_key". So we have hardcoded transition key for every backup which SST script does.
The right way is to enclose $transition_key variable to double quotes to get it real value (randomly generated transition key).