The bug

Consider the following extremely simple use case: I want to activate a camera move that

• starts at one position
• moves to another position over 5 seconds

This is of course trivial to write, it's just two commands:

/camera @a set minecraft:free pos <pos1>
/camera @a set minecraft:free ease 5 linear pos <pos2>

But oops! If you activate both those commands in the same tick, it doesn't work! You'll just be dumped at the second position immediately with no easing!

How to reproduce

1. Place a chain of two command blocks
2. In the first one: /camera @a set minecraft:free pos ~ ~1 ~
3. In the second one: /camera @a set minecraft:free ease 5 linear pos ~ ~10 ~
4. Activate the first one

Expected result
Your camera transitions from low to high over 5 seconds

Observed result
Your camera is immediately high, no transition at all

Notes

Adding a single tick delay to the second command block avoids the issue. Of course, this is *NOT* a viable permanent solution, since commands in functions cannot be delayed!