The bug
TNT blocks that are ignited at high coordinates create a TNT entity with an offset. Depending on the parity of the coordinates the TNT entity spawns approximately half a block to the right or half a block to the left of the original location.
How to reproduce
Teleport to high coordinates (in certain cases this may lead to MC-92916)
/teleport 29999983 ~ 29999983
Place a TNT block and ignite it, for example with flint and steel
→ ❌ The TNT entity is created with an offset
You can also verify that this is not a visual glitch by summoning entities at the positions of the TNT entities
/execute at @e[type=tnt] run summon armor_stand ~ ~ ~ {NoGravity:1b,Invulnerable:1b}
Affects 1.13-pre1