I too am having problems accessing Facebook. It seems to be the only website where I have this issue. I can reach it via 4G on mobile android, but trying across 4 different devices over BT wifi, the page just loads as truncated text on the left hand side of the window. Times New Roman font, some black, some blue. I've added it as an allowed site under parental controls and switched off web protect. Still no joy. Oddly, however, using my work laptop and VPN accessing the same BT wifi, it works just fine!
I also run McAfee total protection, but my vn doesn't have parental controls or an ability to add specific sites.
Would be grateful if anyone has any suggestions, or if a known BT issue? Thanks.