This happened in my game as well, just after getting the radio message to retreat after killing the spotters.

Version:
0.5.102571

Think this is a minor bug, maybe the file is missing :D

This also happened to me.
To the devs:
There really is no need to have a dialogue box pop up to tell a casual user that a texture is missing. The popup breaks the immersion and odds are, they might have never noticed anyway. Instead, you should just capture these errors and output them to a log file for people to see if they're interested. Having these messages pop up in game reminds me of new programmers outputting debug code to standard output.

I got it too

We could not reproduce this bug.

Please let us know if you are still able to reproduce this issue in latest Development build. Thank you.

Closing due to lack of feedback. If this issue is still reproducable for you, please create a new ticket for it or ask for this one to be re-opened.