You are up against it with Huion tablet issues on this forum because AFAIK none of the forum regulars use Huion tablets plus you are using a Mac. You have not been overwhealmed with replies, so I'll see what I can find.
Have had a good look through the Huion driver options? With Windows and Wacom there is an option to 'Use Windows Ink'. A quick Google showed that the Huion driver has the same option, but it seems unlikely that it would apply to your Mac. Also look for a 'UseTabletPC' check box (although that has a Windows sound to it)
Have you looked at the Adobe help page? While most of it relates to Wacom tablets, it does discuss Mac system settings related to pen pressure. Scroll toward the bottom of the page for Mac info
I looked thorught the Driver options but couldn't find anything related to Ink or UseTabletPC. I also looked on the adobe help link but couldn't find the settings for Ink in my computer (not sure if it might be a Wamcom thing only or if my tablet is too old)
I've open a ticket with them, was hoping to hear something here before I jumped on the customer service (saw a lot of people where having a similar issue) I'll keep you posted if it end ups being a psd glitch instead of a software issue on their end