Just encountered a pathing issue after switching bots from regular code to pre-programmed functions. I switched out all of the fire-making code for a function that did the same thing and for most of the bots it was perfectly fine, but I had to re-reprogram 3-4 of them back to the regular code. They made sparks perfectly fine, but kept attempting to get coal from a source that was completely blocked off (all 3-4 chose the same one). The best part was that the coal they were trying and failing to get was surrounded by the largest quantity source blocks, so I couldn't make an opening for them to get to that block.
I had to change them from the function I made (which used "Find and Pick" for all materials) to "Pick From" with a coal source that they could actually access. I didn't have this issue in the previous update of the game that I played 7 months ago, and only a few bots were effected by the change. I don't know if campfire placement was an issue, because I only thought to check the campfire location of one bot, but that campfire wasn't placed very close to that coal or anything.
In case it matters, the unreachable coal in question was at the bottom of a vertical 3-block line of coal. It was surrounded on all sides, unlike the other 2 coal blocks next to it, which had at least one uncovered side. The other bots used the top one in the line, and maybe the middle (but I didn't think to watch for that). I had to change the problematic bots to pick specifically from the top one in the line. The rest of the bots chose that block just using the "Find and Pick" code.