Prevalues from Prevalue source (Umbraco document) won't load after x days.

[Yannis-S-Standaert]

In an Umbraco 8 website using Umbraco forms v. 8.7.5.0 we noticed that every so often, the prevalues of a checkbox list stop working.
To fix it, we have to save the prevalue source again (without changing anything)

The form itself, the prevalue source and the nodes that are listed in the prevalue source have not been changed between the time it last worked and the time when it stopped working, so it's unclear why the prevalues stop working.

Is this a known issue?

As a workaround, I tried using the FormPrePopulate event on the UmbracoFormsController to populate the prevalues myself, but I'm don't understand how to fill them in correctly.

I have to populate them as an IEnumerable of type string, but the FieldViewModel that is used in the razor files to render the field uses an IEnumerable of type PrevalueFieldModel

[Yannis-S-Standaert]

@BoletteKern Is there anything I can do or provide to help reproducing this issue?

[BoletteKern]

Hi @Yannis-S-Standaert, thanks for reaching out! I labeled this issue with the "state/needs-reproduction" for the DXP team to try and reproduce the issue. We will reach out to you if we have trouble reproducing it.