When testing knockback on FE 1.12.2 build 56 I found knockback isn't working properly.
/p group _GUESTS_ zone tst1 true fe.protection.zone.knockback

Please check this video: https://drive.google.com/file/d/1clXn5-UwxvsYqqqa-W41DDzeRCyn9-39/view?usp=sharing

• the effect is given only once when at the border
• add /zone entry tst1 will perform An unknown error occurred while attempting to perform this command

modlist.txt

Verified with FE on vanilla. Build 56