There is a specific issue with the Facebook in-app browser intermittently making requests to websites without cookies that had previously been set. This appears to be a defect in the browser which should be addressed soon. The simplest approach to avoid this problem is to continue to use the Facebook app but not use the in-app browser.
Anyone with a pair of Hunter wellies and Nigel Slater cookbook is drinking gin at the moment, it's hard to escape it. Bars dedicated to the once maligned spirit are popping up everywhere in the capital, most of which you're reading about on here.