columns keep resizing in Column Layout in Mail app, Ventura 13.1 (22C65)

erikselz wrote:

my columns keep resizing automatically, ignoring my override. anyone else experiencing this on new OS update?

Have not heard this issue.

—Quite Mail.app and when you relaunch the app hold the Shift key down, and compare your results.

—Mail, disable any mail plug-in and /or extension and test...

Mail>Settings>General>Manage Plug-ins

Mail>Settings>Extensions

no insight or resolve:

A SafeBoot How to use safe mode on your Mac - Apple Support will sort many anomalies. Login and test, reboot as normal and test.

Have you tried other View option..(?) both check / and uncheck compare your results:

Mail User Guide for Mac - Apple Support