I could boot the same stick on an older PC using an Intel CPU (6th gen). However I noticed that not just the usual two boot entries (UEFI and legacy) were displayed, but several legacy ones. That might be a bug in the PC's BIOS, or maybe that's the issue that prevented boot on the Lenovo TP. I also noticed that during first boot a third partition was created on the USB stick, adding an ext4 filesystem used as overlay filesystem. Usual expectation of a live system is that it does not change the medium it is booted from, at least not without asking for permission to do so, but that might be a different issue.