labeling - Why does a single feature's label not show?

I am working with a GeoPackage layer, and cannot figure out why one of my features' label refuses to be shown. I am using only data-defined labeling for this layer, not auxiliary storage. What things can I troubleshoot to find the cause?

Here's what I've already ruled out:

• Rule-based labeling: labels are displayed by a wordwrap() function; the necessary attributes "name" and "wrap" are correctly populated.


• "Show all labels for this layer" is selected in Label properties.


• "Only draw labels which fit completely" and "Discourage labels from covering" are unselected.


• "Show label" and "Always show": tried setting both to TRUE, without success.



• Scale-dependent and pixel size-based visibility are unchecked.


• The geometry is valid according to both Check Validity and Topology Checker.


• "Simplify geometry" is un-checked in Rendering properties. This is normally the culprit when a single feature is missing its label. If I create a new project containing only this layer, the label WILL be displayed, only if I un-check "Simplify geometry". However, in the project I am using, this does not solve the problem, even after deleting all other layers from the project.

If I split the feature into two new features, the label will show only on the northern of the two. If I split it into two parts of one feature, the label does not show on either part, even if "Label every part…" is selected.

What other settings or conditions will cause a label not to be shown?