When playing on iOS with an XBox Controller, the on screen prompt in the crafting menu shows to use LB to switch tabs up and LT to switch tabs down, however each button produces the opposite effect. Pressing LT scrolls up through the tabs and LB scrolls down.
This has been an issue for at least a year. I do not remember the exact version when it first started.
Can confirm, also only affects Pocket UI. Also relates to my bug (MCPE-183900) as that also only occurs in Pocket UI and when using a controller.