The current beta (in fact the last one suffered from the same issue) shows artifacts when using the Shadows & Highlights filter (legacy 1.6, live filter as well as normal filter) while OpenCL hardware acceleration is active. Deactivating hardware acceleration fixes the issue.
Btw: It's only the legacy version of the filter that shows these artifacts, the standard version seems to be fine.
P.S. I'd love to upload a screenshot but unfortunately I cannot upload my .jpg files (an error message saying "-200" appears). I'd love to document this error message with another screenshot but: "-200" 😉