TNT with unstable=true is not ignited when broken with /setblock or /fill destroy

Can confirm. Related to MC-257055 MC-170158 as well

This behavior likely works as intended; when unstable TNT (when it was the regular TNT!) was added to the game, it was described as 'Hit them for maximum fun', suggesting that the block needs to be touched by a player's hands to be primed. (Beehives and decorated pots have similar on-break properties which are likely also affected in the same way).

However, the /fill or /setblock commands typically behave as if the block was mined in survival mode, so I see this as a bug.

Alright, it appears that people are treating all bug reports about unstable TNT as related. This approach makes sense when the number of bug reports is low (like now). However, when there are significantly more bug reports about unstable TNT, I recommend using a label instead.

Thank you for your report!
After consideration, the issue is being closed as Working as Intended.

Please note, that mechanics of the game may change between updates.
Things such as graphics, sounds, world creation, biomes, redstone, villagers, and animals may not work the same in current versions.

Full Version History – Snapshot Version History – The official Minecraft feedback site

Quick Links:
📓 Bug Tracker Guidelines – 💬 Community Support – 📧 Mojang Support (Technical Issues) – 📧 Microsoft Support (Account Issues)
📓 Project Summary – ✍️ Feedback and Suggestions – 📖 Game Wiki

Relates to MC-269100