Blocks placed on (certain) X or Z coordinates one less than a power of two are able to be clipped into/through by crouching/uncrouching (you can immediately sprint after uncrouching to make it through full blocks) when moving towards the origin.

My attempts to reproduce the bug in a singleplayer world have been much more inconsistent than testing on the realm I share with my friends, where we originally found this bug.
On the realm, Z=127 and 255 have worked, 255 being very consistent. 511 hasn't worked to my knowledge.
In the singleplayer world, X=255 as well as -255 have worked.
Testing in the singleplayer world has accidentally been done with swift sneak III, however in later testing I have been able to clip through doors and into blocks without it, although it is much harder to time.
Swift sneak has not been used in the testing on the realm.

Linked below is a video of the bug at Z=255 on the realm:
https://img.guildedcdn.com/ContentMediaGenericFiles/55c30dfff0bc849d3a8b1b7222076f5c-Full.mp4?w=1920&h=1080

Linked below is also a video of testing done in the singleplayer world at X=-255 (the iron bars were clipped through [with swift sneak III] after the recording was taken):
https://img.guildedcdn.com/ContentMediaGenericFiles/743e25e12e32c907408f34f63583cdfb-Full.mp4?w=1920&h=1080