Odd, as usually WinPE by its nature should not be machine specific.
I have used a PE creator that I used to use for ghost that works on pretty much any machine plug it into.
The only issue would be if yo are coming across bios or uefi systems, which might cause and issue with it to boot
That is true, I created a USB Flash Disk of the boot image and also a Reflect Rescue CD which I can boot off any system.
I think the problem is as Dahak suggested, you may have created one in a UEFI environment then tried booting it on a NON-UEFI system, you need to create a rescue flash disk for each environment.
With regards to Paragon Backup and Recovery, if you do get it, you can simple restore the image in Macrium to the point where you like, then uninstall Macrium Reflect, install Paragon Backup and Recovery and create new images for each system, it's actually much faster than Macrium Reflect and the backup size is much smaller.
How did I found out about Paragon?
When I got my ORIGIN PC Millennium Desktop, they gave me this flash disk for recovery which I am sending you shortly after the 16GB upload is completed; so I called them and asked them what software is actually behind this wonderful backup tool? They told me it's Paragon. that's when I discovered it.
The 2nd reason is I had an Intel 750 1.2TB PCIe SSD, when using Macrium Reflect, the moment I add the Macrium Reflect Recovery Environment to my boot menu options in Windows, the moment I reboot I would get an error that "the authenticity of efi.boot could not be verified". I contact Macrium Support about it and they didn't have a clue they said because it's a PCIe SSD, Macrium is seeing the actual partition letter as letter W: instead of letter C and they are not interested in fixing this bug since barely any people have this PCIe SSD. Very bad support. Paragon Backup and Recovery never failed me. Heck I can even install Windows 7 and back up the partition, then wipe everything and install Windows 10, then using Paragon Backup and Recovery I can restore back to an OS as it will set the partition layout and the smaller partitions before the OS partition exactly the way it was so it's very easy to switch between OSes this way.