Original summary:

"%%" in the attribute.modifier.* strings isn't parsed correctly on Pocket UI

The %% in the attribute strings (such as attribute.modifier.plus.1=+%d%% %s) isn't parsed correctly and doesn't print the % character when playing with Pocket UI. This can be easily seen with speed, slowness, turtle master, and strength potions.

Tested on Android using only the default resource pack and the English US language. This is not an issue when playing with classic UI.

Also tested on Windows 10: not an issue in both classic and pocket UI settings.

Update: it seems to be an issue only when playing with touch controls. I have just tried playing on Android with a bluetooth controller on Pocket UI and the % sign showed up.