Reaction rule throws exception when previewing node
I have found a workaround.

It seems that this is indeed a bug in the Rules module. The working solution is from here (although it was originally written for different situation, it fits this case as well): https://www.drupal.org/project/rules/issues/2929588#comment-12385257, and basically suggests to use a different condition:

Rule condition: 'Condition: Data comparison'
Data to compare (switched to data selection): node.type.target_id (Content type ID)
Operator (switched to Direct Input mode): ==
Value (switched to Direct Input mode): your_node_type


I hope this helps somebody.