Description

When a new citation is inserted while a citation style is selected in Word that makes use of the feature "Reference is cited in a previous footnote", Word crashed at some point. 

Explanation

The problem is caused by the Word update in May 2026, Word Build 20026.20140. We are working on a fix.

Workaround

In the meantime, you can circumvent the problem by using a different footnote style, for example the style "Ebster, Stalzer, 5th ed. (Notes)". It does not use the feature that causes Word to crash and thus can be used without a problem.
Since it is only the insertion that triggers the crash, you can switch again from Ebster, Stalzer to your own style to view your document or hand it in. Your document will be formatted correctly, just avoid inserting new citations while your own style is selected.