Custom Topic items not used in moderate topic view

[Ruud68]

Steps to reproduce the issue

1. create new set of custom topic items
2. set these topic items to category
3. moderate a topic in the (changed / configured) category

Expected result

Topic items should show the icons as setup in new custom topicitems.xml

Actual result

Topic items from default directory are used

System information (as much as possible)

Joomla version: 3.7.5
Kunena version: 5.0.10
Php version:
Database version:

Additional comments

see: https://www.kunena.org/forum/general-questions-and-how-tos/139264-what-kind-of-topic?start=10#194789 for detailed description