Hi! Any news on this? I'm having the same problem as OP, and I also tried latest Safari Technology Preview and error still persists there? Any workaround for this or is it going to be fixed in Safari soon?

I can confirm this bug too. browser.cookies.getAll function is not working in Safari from v 18. it only works if developer tools console is opened.

same issue we encounter. it is bug introduced with Safari 18. @Engineer are there any info on the plans when this could be fixed? thanks