Hi,
Can you please re-download HikaShop 3 in order to be sure that you have the latest version ?
I checked the legacy triggers for the new HikaShop cart system this month and I was able to retrieve the cart limitation system with a little patch in the HikaShop core.
I wanted to be sure that no patch in HikaMarket would be require in order to support HikaShop 3 and, for what I tested with latest build, it was fine. So if with that latest build you still have an issue, we will need to reproduce your problem in our side (and have some details about your current configuration to duplicate it).
Reards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.