No permission to call sandboxed from Pengines / NodeRed / Thea

I am trying to use Pengines in NodeRed to receive a .owl file over MQTT and to load the axioms in Prolog. Ideally, I’d like to have Prolog process the sent file without saving it to the file system, but I don’t see a way to do that. Instead, I’ve been saving the incoming owl to a file and using the thea/owl2_io:load_axioms/1 command to load that file dynamically, but I get this error from NodeRed:

No permission to call sandboxed `'$current_module'(_2660,_2662)'
Reachable from:

Any idea how to fix this or how to avoid writing to the file system in the first place?