I pretty sure it’s very deliberate, whatever the motivation. I’ve seen (somewhere in the many threads on this topic) detailed feedback from Elektron support about why PC works “within the Elektron ecosystem” but no guarantees about what happens elsewhere.
The fact that it doesn’t work with varied track lengths on at least two machines suggests it’s coded not to accept program change when it’s ambiguous where the pattern ‘ends’ (starts to repeat exactly).
EDIT: Link to Elektron feedback on PC.