I get reports from people using latest FF 70.0.1 on Windows only, with extension “I don’t care about cookies” installed, that they randomly see cookie warning not blocked:
Test URL: https://www.paypal.com/uk/signin
It needs to be refreshed at least several times to be caught. I tried it and I was able to reproduce it too (it works in Linux perfectly with same FF and extension version, so it is Windows only), but I’d like someone to confirm it. I’m not sure if it is a Firefox bug although it looks like one, so I haven’t yet reported it.