When a player would die but uses a totem of undying instead, any active status effects (such as strength, swiftness, weakness, etc.) are removed.
Steps to reproduce:
/give @s totem_of_undying
/effect give @s swiftness
/effect give @s instant_damage 1 4
Hi!
This looks to be a duplicate of MC-108821 (which has been marked as Works as Intended).