Topic assignments in course lead to duplicated groups when copying the course

Copying a course with a topic assignment now duplicates existing topic groups. the first time, it creates groups with new names: original topic groups are named "Topic [topic name]"; the groups from copying the course are then named "[topic name]_Group"
Then copying the copied course again, the new topic groups are duplicated, following this pattern:

Original groups:
Topic [topic name]

First copy groups:
Topic [topic name]
[topic name]_Group

copy from copy groups:
Topic [topic name]
2x [topic name]_Group

and so on