With the new 2019 UA Artificer, once per long rest you can 'create' a magical item if you know its infusion. This has a set limit based on level, but once you reach that limit any additional magic items you infuse will negate the last-most item you've created.
If my Artificer fills a bag of holding with TNT, cycles through his other infusions, and then infuses an item mid-combat, will his now defunct Bag of Holding drop its payload for extreme success?
Best Answer
Remember the typical disclaimer about playtest material. I don't think the designers considered that scenario yet. There are two options within the description of Bag of Holding that it could lead to.
Bag is Destroyed
The first is considering the bag "destroyed", which seems the most likely outcome RAW:
Bag is turned out
The other option is consider it to be turned inside out:
Which is much more generous to the player, and in line with the Artificer's Infusion of Many Pockets:
[W]ill his now defunct Bag of Holding drop its payload for extreme success?
Neither of these options would set off the TNT. One them takes the TNT and dumps it into the astral plane. The other dumps the TNT, unlight, on the floor.
Also, keep in mind you can only infuse after just finishing a long rest, so doing so in battle is typically impossible or at least very unwise -- unless you were ambushed at the end of a long rest: