This is your computer's site...
https://www.asus.com/Laptops/ASUS-ZenBook-UX301LA/HelpDesk_Download/
ASUS ZenBook UX301LA
Stuff has been happening regarding sleep mode in your BIOS. I think you should upgrade it. Then we must look at that problem device you've got too. There are two BIOS offerings for you (after clicking "show all") of the
same version & date - but no explanation as to the difference...

One has two A's in its name, one has no A (nor even a name). But when I download the unnamed one, I see this .zip...

Right-click it, & select "Extract all" to get...

I'm confident, after that is installed, your BIOS will be "UX301LA.300
2019/06/25" -- "AS" is stripped off. So, take the "unnamed" one, it matches what you've got now - one "A". The other would give you two. I'll do a Google to see whether I can discover what that is about. I wish there were a readme somewhere.
Read through the following, & ask any further question...
https://www.asus.com/support/FAQ/1040162
Update Notebook PC BIOS to ensure improved password security
(1) Do you have a "Firmware" section in
Device Manager (as in that article)?
If so, that method will make the decision for us as to which BIOS upgrade you should have.
(2) Do you have WinFlash (ask Search)? If so, it can also make the decision.
(3) Otherwise, you will need to do Method 2 -- Easy Flash...
(a) Download UX301LAAS300.zip, unzip it, & copy
UX301LAAS.300 to a USB drive.
(That's the "unnamed" one.)
(b) Enter BIOS Setup. One way is...
"START, Settings, Update & Security, Recovery, Restart Now (under Advanced Startup)"...

That reboots to the "Choose an Option" screen. Choose "Troubleshoot, Advanced Options, UEFI Firmware Settings", then click
Restart to get to BIOS Setup.
(c) In BIOS Setup, at the Advancedtab, you select Easy Flash (as in the article).
(d) Finally, select UX301LAAS.300 on the USB drive, & answer
yes to flash it.
(Try the arrow keys to move around & the Enter key to make a selection.)
The article is showing different screens depending on BIOS & what version of Easy Flash it's got - but the process is the same. Good luck. Post back results or any further question.
If you scroll down the older versions of BIOS that are available at your site, you will see stuff happened regarding sleep mode. Your current version had a fix for it, & the one right afterward also had a fix for it.