Yeah, I had one stock I was trying to buy and it was up ~30% from $0.10 to $0.13 x $0.16. The most they would let me bid was $0.12xx (less than the bid), despite over 100k in volume. It's something based off the prior day's close. You have to get a CSR to uncap every single order that you want and then you can't modify them or it comes back. I will use a different broker next time.
This "feature" predates that by a while. Who knows with those clowns. Best I can tell they have a disconnected group of risk guys and programmers that cook up these algorithms without any feedback from customers or brokers. They then have an uneducated call center team that knows next to nothing, whose only answer to the flat contradictions they spit out is that "we have to follow the algorithm" and who make no attempt, or perhaps are not given any chance, to make suggestions to improve the company. Add to that a management team that appears oblivious to the fact that most of their customers think they're a conspiracy of dunces. And finally you'll have Volpunter butting into this post to tell us how small and worthless we must be because he gets great service from them with his BSD. Best idea is to extricate yourself from them best you can and realize the time you put into building software using their API is just a sunk cost.