This is extremely frustrating. It started happening six months ago, and it is still not fixed; I'm losing all my work because the session ends on my Shopify websites; it also happens to Google accounts, like Gmail, YouTube, Google Docs, etc... I've moved away from Safari, to Google Chrome, but I hate it. The web inspector on Safari is a lot better, and as an iPhone and web developer, I need to test things with all browsers; Apple needs to fix this ASAP.