When we had inquired about the particular bug that you're reporting, it was mentioned that this bug is quite tricky to fix. If I were to hypothesize on why this may be a low-priority bug to work on, I think I would assume that as this is a visual bug, rather than one that is a progression blocker, or one that gives players an unfair advantage, the cost of regressing this bug may not be worth the payoff at this time as the cost could be put towards resolving other more pressing issues.
Rest assured that this issue is surely on their radar, and is most certainly on their list of bugs to fix in due time, so please stay tuned for future updates.
We've done what we could as the CM team to bring your concerns to light, and we appreciate your diligence in assisting Jagex in working towards resolving bugs.
When the day becomes the night and the sky becomes the sea, when the clock strikes heavy and there’s no time for tea; and in our darkest hour, before my final rhyme, she will come back home to Wonderland and turn back the hands of time.