TNT randomly glitches out and at random times destroys blocks when two TNT are symmetrically pushed simultaneously into one place by pistons, unless blocks are used between the pistons and the TNT, *and* there is a time delay.

Whether there is a time delay or not, two TNT symmetrically pushed together onto one place by pistons will cause TNT to bug out AND at random times destroy blocks. Placing blocks between the TNT and the pistons only changes the situation when there is a time delay: one piston completes it's job before the other one, and the delay amount is insignificant. The glitch may happen randomly but will glitch more times than not glitching. The glitch's independence of time delay for the pistons only, may be another bug. The use of a liquid is probably insignificant in either contraptions, although when the glitch decides to destroy blocks, it does so only at times when the bugging TNT is not on top or is at least not visible. This may be because it goes underground where it explodes. It looks as though only one TNT bugs out based on the damage. The plates of the pistons at times, ignore the TNT. Also, the glitch does not work with only one side or one piston.