Can you please investigate this issue thoroughly, I've been playing around with one of my creative mode worlds in single player and some wooden blocks mysteriously vanished, despite the remaining wood blocks not being on fire.

Also Creepers are non hostile in creative mode so this can't be the reason why this is happening.

And on a different world that is on survival this happened to one of my friends fishing shacks, even if a Creeper had exploded, the majority of the time the water would have nullified the explosion, what I'm saying is usually there is some evidence of griefing.

Please look into this extensively, and not just report back with "cannot reproduce" in one day after I write this comment, because there have been other people who experienced issues with certain blocks vanishing into thin air as well and there is obviously some sort of error going on that causes things to vanish without a trace at random, no set in stone length of time, and without warning.

and as far as I know this bug appears to be exclusive to bedrock edition

in Java placed blocks seem to be more stable as there had been less complaints about issues like this. I've got backup files for my worlds but this is beside the point really, 1.16.221 is not very stable and blocks should not be vanishing at random, no wood blocks, not stone, iron, chests or their contained items etc. Stability is important for any game not just Minecraft.