Ottava in custom palette loses customized text in Line Properties when double-clicked onto score

Nightly d45cc19 / Win 7.

This could be related to https://musescore.org/en/node/68271. Open the attached file.

1. Drag and drop the ottava from the advanced palette onto the first note of the first measure. Now select the second measure and double click in another ottava. Note that text properties have correctly adopted the "Style > Text > Ottava" style in both cases.

2. Right-click one of the applied ottavas and select line properties. Delete the tags and enter "8va" in the text fields instead. Save the ottava in a palette. Now repeat step 1 (above).

Expected result: Both operations should give the same ottava with no tag in the line properties dialog box.
Actual result: Drag-and-drop ottava behaves as expected. But double-clicking results in the ottava tag reappearing in the line properties dialog box.