I have been experiencing the following problem which was reported in 2018:
I see that there are some options in the current version (22.214.171.124) for Sorting & organizing, but there does not seem to be an option to have new items (including type-based rules) go to the primary display. I would really like for Fences to respect which monitor is set to primary - which should, by default, receive new items - and which is set to secondary. The issue is persistent, not intermittent.
EDIT: I had the checkbox enabled for "When I plug in a new primary monitor, move my icons to it". Unchecking this resolves the issue, but the wording is incorrect. The primary monitor never changes; you guys should remove the word 'primary' from this description.