Been scurrying through this forum and hadnt seen this one posted anywhere. Ive seen it in a few places in steam but apart from that it seems to be one of the bugs that never got fixed in this game and is also one of the more annoying ones.
There is a bug with lander armor and also the mark II version. Once you equip this to your ship and your lander gets more resistant, so does the wildlife. This means in some cases it can take a long time to kill wildlife on planets
After the bug begins you can circumvent it for a little bit by saving your game. Exiting game to desktop. Then start game back up and load your save. Then the critters on the planet you are at, are back to normal. Once you travel to a different planet tho it slowly starts over again with some of them getting way too resistant.
It has to be said its not every critter that this happens to but it is alot of them and for the longer you play it seems the more that get resistant.
You can undo the bug from your game by unequipping the lander armor, saving your game, exit to desktop, Launch the game again, reload your save. But then you dont have the benefits of the lander armor which is annoying.
Its like once you equip lander armor to your ship it slowly starts creeping up on all the critter wildlife.
I hope you havent stopped looking at this game as its an absolutely super fun franchise and you did a good job with this one as an "upgrade" to the old star control games.