For the last three days, someones been putting in dummy orders...

For the last three days, someones been putting in dummy orders of around 136k each day, and then cancelling the order after trade finishes.

What is the reason they might be doing this? It makes it seem like theres a whole heap of shares for sale, which in my mind suggests whoever is doing this is trying to artificially keep the price lower by incorrectly inferring more people want to sell - is there a reason they might be doing this? (note: I'm not the most experienced investor so welcome any advice as its interesting to watch, but frustrating at the same time).