Possible Retroarch overlay system bug?

[Alturis]

Running on a Pi3.
Accessing files over network from Windows 10 via \\RETROPIE

Its possible that this was some other fluke but wanted to see if anyone had experienced this. I was setting up a new game in my arcade folder and had its cfg setup like this.

ramprt2p.zip.cfg

input_overlay = "/opt/retropie/emulators/retroarch/overlays/arcade-bezels/ramprt.cfg"
input_overlay_enable = True
input_overlay_opacity = 0.900000
input_overlay_scale = 1.000000

video_shader_enable = "true"
#video_shader = "~/.config/retroarch/shaders/crt-pi-curvature-vertical.glslp"
video_shader = "~/.config/retroarch/shaders/crt-pi-curvature.glslp"

ramprt.cfg

overlays = 1
overlay0_overlay = ramprt.png 
overlay0_rect = "0.0,0.0,1.0,1.0"
overlay0_full_screen = true
overlay0_descs = 0 

But I was still working on ramprt.png in Photoshop and had not yet saved it out. I tried running the game to capture a screenshot to use as a guide and it just hung there on a black screen until I had to power off.

Then when I rebooted it repeated this. I looked at the ramprt.cfg file and it was all changed out to mostly garbled xml data it seemed.

Once I had the png in place and restored the ramprt.cfg it is working fine now. But I am wondering if there might be an issue with an overlay cfg file that refers to a missing png?

My other thought is that maybe I had somehow saved the file over the network at just the right moment where it was being accessed that it caused some kind of race condition error.

Edit: Clarification and grammar