When trying to see if MC-133389 happens in 1.13-pre8,i found that /tp Liftski ^ ^ ^3 was invalid. I dont know if this just affects command blocks, but it definitely doesn't seem like its supposed to work.
How to Reproduce:
Grab a repeating command block, place it anywhere, and type the command "tp (player) ^ ^ ^3" and click always active. It will say that /tp (player) ^ ^ ^3 is invalid syntax, while i discovered MC-133389 by discovering MC-133388, which had the command /tp Liftski ^ ^ ^3. This could be VERY bad for adventure maps. NOTE: It does not glitch out with /execute as (player) run tp @s ^ ^ ^3, so the game is certainly bugging out.
Note: As said in a comment, i accidentally hit the spacebar.
?????
Don't put a space at the end of your command.