The a4 slide is definitely odd. As stated, make sure the previous note length is long enough to reach the Slide Trig. Also keep in mind that the SLI parameter adjust the speed of the slide (as well as BND time).
Example: put a trig on step 1 with a note value of C3. Put a trig on step 4 with a value of C4 and while still holding the trig, enable the slide trig. Then on step 1 make sure the note length is 5 or greater. Step 1 should slide up 1 octave by step 4 with speed depending on SLI value.
Going off of memory at the moment as my a4 is packed up for moving this week, but this should work for you.