Hmmm… the sliding usually happens when you walk the character for a certain time but before the time is finished you let him do another animation…however … I don’t see this in your script (the pause after the walking is longer then the walking itself) so I am bit clueless … so this is just a blind shot since I always put does it while right behind the walk command - try it will help.
&ANA walks to spot 1.280 37 0 in zone 2 in 1 AND ANA does it while walk_neutral_loop_rear AND ANA faces left THEN ANA is rear