There is no way the Japs were doing anything but retreating in Aug 45. They were all but thrown back to the home islands by then and the first A bomb dropped on the 6th (?). The was all but over bar the subjugation of the Japanese islands themselves.
You only bury stuff carefully if you want to recover it later or it is of a nature that cannot be destroyed by any other means (ie fire or demolition charges). Since it is clear that there were simple means to destroy them it must be assumed that any burial was intended to hide them temporarily. If, as suggested above, we didn't want to make a gift of them to the Burmese why bury them for recovery? Recovery by whom? Not us if we were planning to leave in a hurry and not return. No point leavng them intact for the Burmese to recover if we intended to deny them the assets.
This line of "reasoning" simply does not hold water, it is completely irrational.
We probably were planning to leave Burma by then and would have been disposing of the vast quantities of stores that we didn't want to/couldn't take home as quickly and easily as possible. Farting about digging vast holes just wouldn't have been feasible time or effort wise. We weren't planning to come back so recovery simply wasn't part of the plan. If we wished to save the aircraft we'd have put them back on the trransport that had got them there in the first place, assembled them and flown them out or burned them in situ. Burial would simply not have been an option.
If anyone thinks otherwise please suggest a scenario where burial would have been considered, and while you're at it, list all the other scores/hundreds of sites there must have been elsewhere in the world where such massive scale burials of pristine equipment have occurred, because they must have been documented (they can't all have been un-documented can they?) and also list all the ones that have subsequently been dug up again, because they can't all have been left unmoleseted, such is the interest in finding WW2 artifacts these days.
The absence of evidence following both those requests will tell it's own story in illustrating the unfeasibility of this particular scenario and why it surely falls into the category of pure myth, just like all the hundreds of other mythical "burials", none of which have ever been found.
Its a fairytale.