Bingo! Check with Lenovo's support to see if they have a firmware upgrade or any solution for this issue. With any luck, you can solve it without spending any money. (Or just go wireless on that system instead of using ethernet).
This issue affects a handful of vendors/chipsets, but I don't know which specific products to avoid, nor do I know which ones were good. I don't have any recommendations to give. Sorry about that. My best suggestion is to read reviews. Or, get something that is new on the market -- the problem is likely to have been addressed in the last few years since it first started crashing networks.
I think that unplugging ethernet from that docking station will ultimately resolve the core issue (getting a good replacement is a secondary one, but unrelated to OpenWrt). When you feel confident that the problem has been solved... please consider marking this topic as [Solved]. See How to mark a topic as [Solved] for a short how-to.
Thanks! 