Bug report #21108

Updated by Jürgen Fischer over 3 years ago

Load the layer Matteo posted at #18153. https://issues.qgis.org/issues/18153.
The symbology is applied correctly.
Open layer properties (you don't even have to go to the symbology tab) and click apply or OK, and the symbology will be lost!
Load the qml again from layer properties>symbology. The symbology is loaded correctly, but lost on apply or OK.
Load the qml again from layer properties>symbology, then edit one of the values (you don't have to actually change it, just click it to edit, then click out of it). The symbology is not lost on apply or OK. (Save as a new qml and that won't have the same issues - woohoo - a workaround!).

Yes, this issue is relatively minor, but I imagine it'll cause a lot more headaches as LTS users start to move to 3.x.
It occurs in QGIS 3.4.4 and I believe all earlier versions of 3.x.