I've had this problem too, and (with some help on reddit) I found a pretty easy, permanent solution.
By heading to the game's folder - or copy and pasting
%localappdata%\packages\microsoft.minecraftuwp_8WEKYB3D8BBWE\localstate\games\com.mojang\minecraftpe
into the Run program in the Windows taskbar, you can click options.txt, and find a option called chat_typeface:1, and set it to 0. That should fix it.
Alright thanks, I didn't see that post on the search feature.
David Punzalan
I've had this problem too, and (with some help on reddit) I found a pretty easy, permanent solution.
By heading to the game's folder - or copy and pasting
%localappdata%\packages\microsoft.minecraftuwp_8WEKYB3D8BBWE\localstate\games\com.mojang\minecraftpe
into the Run program in the Windows taskbar, you can click options.txt, and find a option called chat_typeface:1, and set it to 0. That should fix it.