Sometimes when sprinting across a 1 block ditch you will not fall through. This is likely to be related to random fall damage due to lag. I first experienced this in 1.3.
I have a video demonstrating this.
If the attachment doesn't work try: http://youtu.be/FTetKnm7EVY
Related issues
is duplicated by
MC-2354
walking over water in survival
MC-2454
Jesus walking on water
MC-6008
players can run over 1 block gaps
MC-11148
Running over 1 block wide gaps
MC-17063
You can run over a one block water source while sprinting.
MC-58163
Walking off block acts unexpectedly
MC-74254
Sprinting across gaps doesn't fall
MC-91662
Can Run across 1 block gaps
MC-97646
Players able to sprint over 1 block gaps without jumping
MC-179559
Walking Diagonally Across Farmland
MC-212361
Player can run on the air block (sometimes)
MC-233434
You can run on Blocks that aren't connected each others (1 block of distance) without falling. It works only in some cases.
MC-270877
Able to walk across one block gaps.
MC-280176
Crossing gap without jumping
MC-297895
Players walks on Air
relates to
Attachments
Comments
migrated
migrated
That is an intended feature.
migrated
Explain why then this is random?
migrated
You can only clear exactly one block gap when fully sprinting. If you go at the gap at a slight angle you won't clear it. Also trying to go over with only a little start of 1-2 blocks you also won't make it because your sprint isn't fully engaged. Can seem buggy but it's just very strict about the circumstances. Maybe it could be changed to allow a bit more leeway so you wouldn't have to go straight in a cardinal direction but couldn't still clear wider gaps.
migrated
Running over a single block gap works as intended. See Teijo's comment for more information as to why it may randomly seem to not work.
COMETC2021A1
But it seems "fixed" in 1.20.5 pre2.