On macOS 15.5 (Sequoia), there’s a brief white flash when closing plugin windows in Renoise 3.5.x — reproducible across multiple VST3s. There’s also a rendering artifact when resizing the Redux plugin in Logic Pro.
I documented the issue here with a video and system specs:
macOS 15.5: UI Flash & Resize Artifact in Redux 1.4 Under Logic Pro 11.2.1
Would love to know if it’s on the list, or if further info would help.