This command outputs different text in singleplayer vs. multiplayer. On singleplayer, you get a "true hey" message in chat while on multiplayer you get a "1 hey" message in chat.

/tellraw @s {"translate":"%s %s","with":[true, "hey"]}

This is caused by the serialization process for components using nbt now which does not preserve boolean information. When the component is serialized to NBT the arguments ("with") becomes

[{"":1b},{"":"hey"}]

and when the client deserializes that, it reads the 1b as a numeric 1 byte which is then displayed as a 1.