Here are two commands which are both invalid:

/tellraw @a {"text":"Hover","hoverEvent":{"action":"show_item","value":"{id:\"minecraft:stone\",tag:{display:{Lore:[\"Lore line 1\",\"Lore line 2\"]}}}"}}

/tellraw @a {"text":"Hover","hoverEvent":{"action":"show_entity","value":"{name:\"Skylinerw\",type:\"Creeper\",id:\"00000000-0000-0000-0000-000000000000\"}"}}

Both commands have hoverEvent as an option.
The first command has show_item as its action. Although it can be run successfully, it displays Invalid Item! successfully since it is syntactically incorrect.

What I expected to happen for the last command was...:
Since the command is syntactically incorrect, it should display Invalid Entity! instead.

What actually happened for the last command was...:
It rather crashes the game when hovering over the invalid text. It wasn't like this in the older versions, was it?

Here is a video I have attached below. As you can see, when I have hovered over the last invalid text, the video freezes at the near end of the video, meaning that the game has crashed.