I haven't figured out how to reproduce this issue

This is an occasional issue I have noticed recently that only appears to effect certain radio backpacks during a game, in one of the matches I was in I was able to disable one radio backpack but not the second radio backpack right next to it, I did not check how many supplies the back pack held at that point, in another match I was unable to disable or destroy the enemy radio backpack when I found it despite using tifle fire and grenades, my teammate was also unable to destroy or disable it, that radio backpack had the full 100 supplies in it.