Editing and Regrouping Masks Causing Card Progress Loss in Anki

I’m experiencing a problem when editing existing grouped masks. For example, if I want to add a new mask or edit an existing one, I first ungroup the selection, make the edits, and then regroup the selection. This process works about 90% of the time. However, sometimes when I follow the same steps, I encounter an error such as:

No cloze ⁨15⁩ found on card. Please either add a cloze deletion, or use the Empty Cards tool.

When this happens, the edited group of masks is treated as a new card, causing me to lose my learning progress on the original card.


I’ve tried several solutions, including:

Solution 1 : Grouping masks one by one using Shift (sometimes works).

Solution 2 :First selecting the old masks without ungrouping them, then adding the new/edited ones to the selection.

Solution 3 : Making the old group smaller, creating a new group, then selecting both the old and new groups and grouping them together (this method consistently works and preserves my card status as “green”).

Anki Versions tested: 25.05 Beta 2, 25.02.1, and other recent versions (Windows, Qt6)
OS: Windows 11
Hardware: Intel Core i5 (6th Gen), 16GB RAM

this is a sample of the deck that i have used :
[Regrouping Masks.apkg](https://github.com/zakivx/ankitest/blob/main/Regrouping%20Masks.apkg)

No source file, test, or code entry point is named. Reproduce the problem with the attached “Regrouping Masks.apkg” while ungrouping, editing, and regrouping masks, then trace the mask-regrouping path; done means the original card progress is preserved and the missing-cloze error no longer occurs.

Written by the indexing model from the issue text.