calendar widget sets date to previous day

[falkmielke]

What is the bug or the crash? What were your expectations and what actually happened?

When clicking the date widget and selecting a date, the field gets filled with the previous date.
(The visible date, i.e. the wrong one, gets written to the attribute table.)
This happens on a test project, and on a live environment with postgresql backend.

https://github.com/user-attachments/assets/e6729739-d716-4c18-9942-ce15201f95ae (android screencast / stvav1 in webm, no audio)

I saw #1705, but think the issue there is different.

Thank you in advance for the support!

Steps to reproduce the issue

• open QField
• open "Live QField Users Survey Demo"
• add a feature
• select a date for "Since"

Version

v4.0.4 / latest

Operating system name

Android

Operating system version

LineageOS 23.0 (Jan 13, 2026)

Reinstall QField

• I have a fresh install of the latest QField version, but the problem persists.
• Problem can be reliably reproduced, doesn't happen randomly.
• Problem happens with all files and projects, not only some files or projects.

Additional context

I do not know the data backend of the test project, but also observed this behavior on interaction with a postGIS backend. Timezone and date settings of the server are checked and okay.

I suspect the error to be Qt-related; found some hints in src/qml/imports/Theme/QfCalendarItem.qml. However, I lack knowledge of Qt. Could either be the calendar.locale, or the start day of the week (DayOfWeekRow).

Timezone here is Europe/Brussels.