App crashes when undoing a 'Replace All' function

[raspberrygable]

What happened?

iOS 26.1: The app (full paid version) crashes after attempting to undo a Find + Replace using Regex.
Have not yet reproduced such a crash resulting from any other triggers.

What are the steps to reproduce?

1. Successfully ran Find + Replace (Regex).
2. Hitting 'undo' afterwards crashed the app.
3. Reopened the app
4. File I'd just been working on was not visible in 'Recent Files' pane; had to manually locate it
5. When file located + reopened: changes had reverted to pre-Find-and-Replace state (i.e. the 'undo' function appears to have worked, but triggered the crash in some way).

What is the expected behavior?

I hope that Runestone can be updated to tolerate the user applying 'undo' following Find + Replace functions (or any other functions) reliably and without crashing.

[ranty-fugue]

This is a real problem for me, as I (would) use this functionality all the time, and afaict, there’s no reasonable workaround for many cases. There doesn’t seem to have been any movement on this for six months… Any chance you take a look somewhat soon?

[KGoodacre]

I've experienced the same issue. The app would crash when using the "replace all" feature. Or it'll just crash randomly during normal use, I'm currently running iOS 26.5.2.