For curiosity (as I don't use Text Overlay function), I tried on my cams v 5.2.5 and I have the same results as pepperfr, only Line 1 displays on screen, the others layers appears also over line 1 on screen:
This overlay was created by my VMS without using OSD from Hik cam:
Now if I try to use Hik cam overlay :
and the results on my VMS as you can see, the 4 lines are at same place (look the numbers) :
Again, I don't use OSD layers from cam, but for sure the problem exist with osd and overlay lines, even with v5.2.5.