What was the issue ?

I can't reproduce this on macOS 12.3.1 with Qt 6.3. Works as it should.

Hi and welcome to devnet, Based on this Apple doc, one possible path could be to create a NSImage from the symbol and then a QImage/QPixmap from it.

I forgot about that one ! It has also bitten me on several occasions. Glad you found out and thanks for sharing :-)

Please report this as a bug in JIRA, with a minimal test case, so that we can check whether this is a 5.15 regression, a Big Sur issue, or something also present in Catalina.