Fire blocks are not extinguished if firetick is off when the block the fire is attached to is destroyed. Instead the fire becomes invisible but still emits light and sets entities on fire that touch it.

Reproduction steps:

1. Create a new Minecraft creative world and turn off fire tick in the settings.
2. In creative mode, place down a flammable block.
3. Ignite the top of the block.
4. Break the block.
5. Step into the space where the block was and note the fire UI.

Observed results: The fire is still there, it was not extinguished.

Expected results: The fire block is replaced with air when the block it is attached to is destroyed.

Repeating these steps with fire tick turned on will cause the fire to disappear as expected.

Note: I saw this has been reported in MCPE-131704 but it was closed as the report didn't explain the steps. I decided to create a new report with a more detailed description of the problem as the original post made it sound like it might be a world generation glitch.