Notebook Hardware and Upgrade Questions

Got my new x360 last week and the fans turn on within a minute or two of starting up at full or near full speed and never turn off regardless of how idle the machine is. Looking for any ideas to try. Basically, it appears that once they go on, they seem stuck on despite being at very low temp & full idle. Only system sleep or shutting down stops the fans. System specs: Spectre x360 15t-df000 CTO, 16GB RAM, 512GB SSD.

• It's not heat or speed because it doesn't matter if the cores are all below 38C and 897Mhz (lowest speed) and the processor is doing nothing in safe mode. I've even tried setting the max processor speed to 40%. Still never shuts the fans off. (checked temps with both CPUID HWMonitor and Intel Extreme Tuning utility).

• Doesn't matter if it's on battery or wall power, charging or not.

• Tried all Power Options and "Best Battery Life".

• Tried Passive and Active cooling settings and setting everything in the power plan to "minimal", "best battery life" and lowest performance.

• Checked to make sure the "always run fans" BIOS options is off (and even tried it on).

• Updated to the latest firmware (.09) and installed latest updates and drivers from HP site and MSFT. Tried HP diagnostics.

• Updated Windows 10 Pro to 1809. Tried a System File Check.

• I tried undervolting with ThrottleStop.

• I've done a lot of internet searching and tried every suggestion I could find short of opening it and repasting the CPU (which I don't think will matter because the issue is NOT the temps (system, cores, or GPU).

• Tried booting in safe mode and then killing everything I could via Task Manager just in case some rogue process is locking the fan shut-off.

I'd also be curious to know from anyone with the gem-cut 15" at what temps your fans turn on and, most importantly, at what temp they turn off.

My last resort before sending it back will be a full Windows reinstall. Can anyone think of anything else to try?