issues with painting

I get repeated messages from the console and the application exits with the (13) exit code.

QPainter::begin: A paint device can only be painted by one painter at a time.
qtloader.js:382 QPainter::setCompositionMode: Painter not active
qtloader.js:382 QBackingStore::endPaint() called with active painter; did you forget to destroy it or call QPainter::end() on it?
qtloader.js:382 QPainter::begin: A paint device can only be painted by one painter at a time.
qtloader.js:382 QPainter::setCompositionMode: Painter not active
qtloader.js:382 QBackingStore::endPaint() called with active painter; did you forget to destroy it or call QPainter::end() on it?
qtloader.js:382 QPainter::begin: A paint device can only be painted by one painter at a time.
qtloader.js:382 QPainter::setCompositionMode: Painter not active
qtloader.js:382 QBackingStore::endPaint() called with active painter; did you forget to destroy it or call QPainter::end() on it?

I am using chromium  80.0.3987.149 on Linux / Wayland

The components used in my application include a Qwt plot. I'll try to remove it and see if that's the issue.