Is your MC spot directed before the walking animation as she needs to walk from a specific spot to begin with which may mess up your code.
Maybe try this?
INT. YOUR BED - DAY
&cut to zone 2
&zoom on 509 249 to 60% in 0
&DOG 1 spot 1.280 173 77 in zone 2 AND DOG 1 faces (left or right) AND DOG 1 is idle_down_sleep_loop
&MC F moves to layer 2
@MC F walks to spot 1.280 304 51 in zone 2 AND MC F faces right THEN MC F spot 1.280 238 70 in zone 1 AND MC F is pet_dog_kneel_happy_loop
@pause for (length of time)
&DOG 1 is transition_down_to_sit
MC F (talking animation or petting animation)
Want to go for a walk?
@DOG 1 is idle_wag_loop
@pause for 2
&DOG 1 walks to spot 1.280 -21 87 in zone 1 AND DOG 1 faces left
@MC F walks to spot 1.280 109 75 in zone 1 AND MC F faces left
@transition fade out black in 1