Safari Preview 143 on macOS 12.3.1 (21E258) on a macMini M1
I didn't see this "flashing" with prior combinations of Safari TP and macOS.
The test case loads a mostly blank page for me on STP 144, Chrome and Firefox. Is there something wrong with the test case?
The Page needs the HTMLModelElement feature activated.
Still loads on iPadOS15.5 beta 3 Safari. I only have access to TP143
Created attachment 458603 [details]
Should look similar to this
The test case only provides a source of type USDZ, no other format
Created attachment 458731 [details]
macOS 12.3.1 (21E258)
with STP 144
still shows the delayed execution of Scene start behaviour.
See black text panels flashing up on page reload in the uploaded screen recording.
Problem persists with STP 145 on macOS 12.3.1 (21E258)
seems fixed in iPadOS16beta