https://www.cnet.com/roadshow/news/ford-recalls-f-150-transmissions-and-more/

Ford has five accident reports that might be related to this problem. The automaker also received one report of "whiplash," which likely occurred when the vehicle lurched forward during the downshift. Thankfully, all it takes to remedy the issue is applying a software update to the powertrain control module, which Ford will handle at dealers.

Unintended first-gear downshifts can really catch you by surprise.