I tried fetching just one sub-project from a branch/variant, it was working from MKS as well as from command line, but when I tried using for example : #/Root_Project#Sub-project/Sub-sub-project#d=variant_name where

my branch was created from Sub-project to its children, the fetch of Sub-sub-project failed using plugin.

If I fetch from Sub-project e.g. #/Root_Project#Sub-project#d=variant_name then it succeeded.

Error :
Preparing to execute si projectinfo for #/Root_Project#Sub-project/Sub-sub-project#d=variant_name
An API Exception was caught!
The project #/Root_Project#Sub-project/Sub-sub-project#d=variant_name could not be located on the server [removed by poster]:18000: MKS125319: For subproject Sub-sub-project/project.pj the variant subproject on development path variant_name cannot be accessed because it is not part of the current project configuration and is not eligible to be accessed from the specified configuration: MKS125320: subproject Sub-sub-project/project.pj is not the root of development path variant_name.
si projectinfo --user=[removed by poster] --port=18000 --hostname=[removed by poster] --project=#/Root_Project#Sub-project/Sub-sub-project#d=variant_name – returned exit code 128
Finished: FAILURE

Using command line, this is working :
si projectinfo --project=/Root_Project/Sub-project/Sub-sub-project/project.pj --devpath=variant_name

si createsandbox --project=/Root_Project/Sub-project/Sub-sub-project/project.pj --devpath=variant_name .

I tried working around it,
instead of using :
#/Root_Project#Sub-project/Sub-sub-project#d=variant_name
I used :
/Root_Project/Sub-project/Sub-sub-project/project.pj --devpath=variant_name
but to no avail..